Q.630.7 It6c no. 899 1980 cop. 5 r UNIVERSITY OF ILLINOIS LIBRARY AT URBANA-CHAMPAIGN AGRICULTURE Digitized by the Internet Archive in 2011 with funding from University of Illinois Urbana-Champaign http://www.archive.org/details/insectpestmanage91980univ CIRCULATING COPY AGRICULTURE LIBRARY 1980 Insect Pest Management Guide FIELD and FORAGE CROPS You must be certified as a pesticide applicator to use restricted-use pesticides. See your county Extension adviser in agriculture for information. FEDERAL AND STATE LAWS The U.S. Environmental Protection Agency is classifying pesticides for "general" or "restricted" use. Anyone ap- plying a restricted-use pesticide must be certified. Only a few pesticides have been classified. Commercial applicators who apply restricted-use pesti- cides must be certified. Commercial applicators include not only persons applying a pesticide for hire but also governmental personnel, chemical company representa- tives, and others involved in demonstrational, regulatory, and public health pest control. Certification as a commer- cial applicator requires passing a written examination administered either by the Illinois Department of Agricul- ture or the Department of Public Health. Private applicators who use restricted-use pesticides "for the purpose of producing any agricultural commodity on property owned or rented by him or as exchange labor (no compensation) on the property of another" must also be certified, either by attending an educational training program or by passing an examination. Educational training programs for farmers (private applicators) and commercial pesticide applicators are con- ducted by the Cooperative Extension Service to prepare persons for certification. For additional information, con- sult your county Extension adviser in agriculture. The actual certification and the issuing of permits or licenses are handled by the Illinois Department of Agriculture or the Illinois Department of Public Health. Special Local Need Registrations Section 24(c) of the amendments to the Federal In- secticide, Fungicide, and Rodenticide Act of 1972 allows states the right to register pesticides for use within the state to meet special local needs (SLN). The authority for state registration of pesticides is the Illinois Depart- ment of Agriculture. A special label, which lists the new Asterisks (*) are used throughout this circular to indi- cate insecticides classified for "restricted" use by the U.S. Environmental Protection Agency. Consider all grain fumigants as restricted-use insecti- cides. 24(c) uses, is printed by the formulator. A copy of this label must be in the possession of the operator during application of the pesticides. In the following pages, all SLN, or 24(c), registra- tions are indicated by this sign: f. Insecticides and Classifications At the time this publication was in preparation, only a few of the insecticides listed below had been classified for either "restricted" or "general" use by the EPA. Addi- tional insecticides are expected to be classified before the 1980 planting season. Your county Extension adviser will have additional information on insecticide restrictions. The chemical names used in this circular may be un- familiar to you. These names are the common, coined chemical names and as such are not capitalized (for ex- ample, terbufos). Trade names are capitalized (for exam- ple, Counter). In the table of limitations (Table 10), the trade names are listed first, with the common name in parentheses following the trade name. In the tables of sug- gestions, the common name is listed first and the trade name is in parentheses. For questions, refer to the list shown below or to Table 10. Table 1. INSECTICIDE CLASSIFICATIONS Common name Trade name Classification azinphosmethyl *Guthion restricted carbaryl Sevin, Savit unclassified carbofuran *Furadan restricted15 carbophenothion Trithion unclassified chlorpyrifos Lorsban unclassified diazinon diazinon unclassified dimethoate Cygon, Defend unclassified ethoprop *Mocap restrictedb fonofos *Dyfonate restricted1* malathion Cythion, malathion unclassified methidathion Supracide unclassified methomyl *Lannate restricted8 methyl parathion *methyl parathion restricted methyl parathion *Penncap-M restricted ( microencapsulated ) phorate Thimet unclassified phosmet Imidan unclassified terbufos Counter unclassified toxaphene toxaphenc unclassified trichlorfon Dylox, Proxol unclassified tt All formulations except water-soluble packages are restricted. b Liquid formulations are restricted. UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN COLLEGE OF AGRICULTURE COOPERATIVE EXTENSION SERVICE In cooperation with ILLINOIS NATURAL HISTORY SURVEY CIRCULAR 899 (revised annually) November, 1979 GENERAL SUGGESTIONS FOR INSECT CONTROL The type of crop rotation influences to a great extent whether or not a soil-insect problem will occur and what kind it will be. Some guidelines follow for predicting soil- insect problems in corn and for determining the need to use a soil insecticide at planting time. Exceptions can be expected occasionally because soil-insect problems are in- fluenced by a variety of tilings unrelated to crop rotation, such as the weather, soil type, planting date, hybrid used, tillage, and natural enemies. Knowledge about soil-insect damage in a particular field during previous years is also helpful because infestations tend to occur in the same fields and in the same area. The potential for soil-insect problems in corn after soybeans is generally low, and the use of soil insecti- cides rarely pays. In most fields, a diazinon planter-box seed treatment will be adequate to protect against attack by seed-corn beetles and seed-corn maggots. Corn rootworms rarely cause damage to corn after soybeans. An exception may occur when corn rootworm beetles are attracted to, and deposit their eggs in, soybean fields that are weedy or that contain volunteer corn. When such fields are planted to corn the following year, economic damage may occur. Good weed control will reduce the attractiveness of soy- bean fields to rootworm beetles and permit soybean-corn rotations with noneconomic damage from corn rootworms. White grubs are an occasional problem in east-central Illinois in corn after soybeans. The potential for rootworm damage in corn after corn is moderate to severe in the northern two-thirds of Illinois, and a rootworm insecticide may be needed. Wireworms are occasionally a problem in the southern portions of Illinois. Wireworms and white grubs are potential problems, in corn after grass sod. Apply a soil insecticide at plant- ing time. Grape colaspis, grubs, wireworms, and cutworms are potential problems in corn after clover and alfalfa. In northern Illinois, rootworms are occasionally a problem in corn following clover or alfalfa. Apply a soil insecticide at planting time. There is a slight potential for damage by wireworms, seed-corn beetles, and seed-corn maggots in corn after small grain. In most instances, a diazinon planter-box seed treatment will be adequate. If wireworms are present, use a soil insecticide at planting time. CORN ROOTWORM SITUATION, 1980 Moderate to severe damage by western and northern corn rootworm larvae can be expected in many fields of corn that follow corn in the northern two-thirds of Illinois in 1980 (see map). The potential for damage south of a line from Belleville to Lawrenceville is low, although an occasional field may sustain economic damage. These pre- dictions are based on a survey of rootworm beetle popu- lations taken in August, 1979. CORN ROOTWORM POTENTIAL, 1980 LIGHT TO NONECONOMIC The populations of western and northern corn root- worm beetles were slightly higher in most counties during 1979 than they were in 1978. Beetle numbers were still lower, however, than those observed in 1976-77. The west- ern corn rootworm continued its southward movement and has now been found in every county in Illinois except Pulaski and Alexander. Corn growers should base the need for using a soil insecticide in 1980 on the abundance of rootworm beetles in cornfields in August, 1979. If the rootworm beetles averaged one or more per plant at any time during late July or August, 1979, plan to use a rootworm soil insecti- cide if the field is to be replanted to corn in 1980. Fields of corn planted in late May or June, 1979, may have extensive rootworm damage if replanted to corn in 1980. Rootworm beetles seeking pollen and silks to feed on during August, 1979, very likely were attracted in large numbers to late-planted cornfields. Millions of eggs may have been laid in these late-planted fields of corn. Planting those fields to a crop other than corn in 1980 will help reduce the overall rootworm populations. During 1979, moderate to heavy rootworm damage was reported in some fields treated at planting time with soil insecticides. Several factors may be responsible for poor or marginal control. Lack of moisture for several weeks following planting may be a factor. Rainfall is necessary to move the insecticide down to the zone where rootworm eggs are hatching and larvae are feeding. In addition, the insecticide rates were too low in some fields. The rate per acre depends on the row spacing (see Table 2 for sug- gested rates). Rootworm resistance to the organic phosphate and carbamate insecticides also may be developing in some fields. Laboratory tests indicate that to kill rootworm beetles slightly higher rates of insecticide were needed in 1979 than in 1972. Although these data on rootworm re- sistance are not conclusive, they are a warning sign for the future. Whenever insecticides, regardless of type, are used continually and extensively over a large area, in- sect resistance to those insecticides is likely to occur. SUGGESTIONS FOR ROOTWORM CONTROL, 1980 Crop Rotation This method is the most effective way to prevent dam- age by corn rootworm larvae. If feasible, do not grow corn 2 years in succession in the same field. Corn root- worm beetles deposit the vast majority of their eggs in fields of corn. Consequently, when a crop other than corn is planted in a field with soil containing millions of root- worm eggs, millions of larvae will perish and will not emerge as egg-laying beetles. The larvae hatching from rootworm eggs cannot survive on the roots of broadleaf weeds or broadleaf crops (soybeans or alfalfa). In a few rare instances, rootworm damage has occurred when corn was planted after soybeans where there was an extensive infestation of volunteer corn or weeds in the soybeans during August. Rootworm beetles were attracted to these weedy fields of soybeans to deposit eggs. Corn following alfalfa may benefit from an insecticide treatment because rootworm beetles occasionally deposit their eggs in alfalfa fields during the bloom stage in August. Soil Insecticides Planting-Time Treatments. Apply terbufos (Coun- ter), fonofos (Dyfonate), carbofuran (Furadan), chlor- pyrifos (Lorsban), ethoprop (Mocap), or phorate (Thi- met) in a 7-inch band ahead of the press wheel at the recommended rate (see Table 2). These soil insecticides will give 50- to 70-percent control of corn rootworm larvae, which is adequate to prevent economic larval damage in most fields. In some heavily infested fields, enough larvae may survive to cause economic root damage. Planting-time treatments applied in early April may give marginal con- trol. Consider a late-May cultivator application in such fields, rather than a planting-time treatment. During 1977-79, rootworm control research was con- ducted at 25 sites in Illinois. Terbufos (Counter) gave effective control in 24 of 25 tests; carbofuran (Furadan), in 22 of 25; fonofos (Dyfonate), in 22 of 25; phorate (Thimet), in 22 of 25; ethoprop (Mocap), in 20 of 25; and chlorpyrifos (Lorsban), in 18 of 25 tests. Control in these tests was considered marginal for a treatment if AGX enough roots were damaged by larvae to cause yield losses. CAUTION: These tests do not necessarily indicate that similar results would occur in 1980. NOTE: If a soil insecticide gave good results in 1979, it will probably provide adequate control in 1980. Exceptions have occurred when a particular insecticide has been used for several consecutive years in the same field. If an insecticide gave poor control last year, switch to another one in 1980. Research conducted during 1976-78 indicates that switching from a carbamate (carbofuran) to an organic phosphate (terbufos, fonofos, chlorpyrifos, ethoprop, or phorate) may be desirable, particularly if carbofuran has been used for several consecutive years. In fields where carbofuran has provided poor rootworm control, it is ad- visable to wait longer than a year before using carbofuran again. If control with an organic phosphate was poor last year, switch to a carbamate (carbofuran). A word of caution about rotating classes of soil insec- ticides: The performance of an insecticide that gives only fair control of rootworms will not be improved by alter- nating it with other insecticides. But the performance of an insecticide rated fair might be improved under favor- able weather conditions or with light infestations. Liquid formulations of carbofuran (Furadan 4F) or fonofos (Dyfonate 4E) may be mixed with water and applied as a spray in a 7-inch band ahead of the press wheel or mixed with liquid fertilizer and used with a split- boot applicator at planting time. Ethoprop (Mocap 6E) is labeled as a band spray mixed with water. Some farmers have had problems with compatibility or crop injury when using liquid insecticide-fertilizer treatments at planting time. The liquid insecticide MUST be compatible with the liquid fertilizer. Conduct a test to make certain the mix- ture is physically compatible before planting. Maintain agitation in the tank after mixing and during application. Use caution when handling liquid formulations. They are more toxic than granular formulations. Cultivator Treatments. Apply granular terbufos (Counter), fonofos (Dyfonate), carbofuran (Furadan), ethoprop (Moqgo), or phorate (Thimet), in a band at the base of throlants just ahead of the cultivator shovels. Table 2. SOIL INSECTICIDES SUGGESTED FOR CORN ROOTWORM CONTROL AT PLANTING TIME, 1980 Class Relative effectiveness* Ounces of product per 1,000 ft. of row Pound !s of product needed per acre Insecticide 40" rows 38" rows 36" rows 30" rows Counter 15G organic phosphate good 8 6.7 7.0 7.4 8.7 Furadan 10G carbamate fair-good" 12 10.0 10.5 11.1 13.3 Dyfonate 20G organic phosphate fair- good 6 5.0 5.3 5.6 6.7 Thimet 15G organic phosphate fair-good 8 6.7 7.0 7.4 8.7 Mocap 10G organic phosphate fair 12 10.0 10.5 11.1 13.3 Lorsban 15G organic phosphate fair 8 6.7 7.0 7.4 8.7 "This chart gives a general comparative rating based on Illinois research data using root ratings as a criterion during 1977-79. Under unfavorable conditions some insecticides rated good or fair may give erratic or poor results. Under favorable conditions, control may be better than indicated. b Rootworm control in research trials with Furadan has generally been good, except in some fields with a history of continuous Furadan use. Cover the granules with soil. The best time to apply a basal treatment of a soil insecticide by cultivator is in late May or early June, near the beginning of egg-hatch. Such a treatment may be more effective than planting-time treat- ments in early April. Control of Rootworm Beetles Use insecticides to control rootworm beetles where pollination damage may occur because of silk clipping. Re- search on spraying the beetles to prevent egg laying and thus eliminate the need for a soil insecticide the next spring has produced variable results. A single soil-insecti- cide treatment has usually been as effective as treating to control beetles in late July or early August and applying a soil treatment the following spring. Some growers may choose to experiment with the management concept of spraying rootworm beetles with carbaryl (Sevin 4-Oil) to prevent egg laying, with the objective of eliminating next year's larval infestation and the need for a soil insecticide. If so, we encourage growers to use the scouting services of a pest management consultant to monitor fields. A properly managed adult-suppression program will require weekly scouting during July and August. Even proper timing and application of an adult-suppression spray does not guarantee success. Factors beyond the control of the operator, such as weather and beetle migration, may mini- mize the treatment's effectiveness. SCOUTING TO DETERMINE ROOTWORM POTENTIAL The abundance of rootworm beetles in a cornfield is an excellent indicator of future rootworm problems. Corn growers can determine the potential for rootworm damage in 1981 by counting western and northern corn rootworm beetles from mid- July through August, 1980, in this way: 1. Make 3 or more counts for western and northern corn rootworm beetles at 7- to 10-day intervals between mid-July and late August in fields to be replanted to corn. 2. Count the total number of western and northern corn rootworm beetles on 50 plants each time. Examine 10 plants selected at random in 5 areas of the field. About 45 minutes would be required to make the counts in a 40-acre field. 3. Move quietly as you approach a plant to avoid dis- turbing the beetles. Count the beetles on the entire plant, including the ear tip, the tassel, the leaf surface, and be- hind the leaf axils. 4. Record the number of beetles you find per plant. If the average is more than one beetle per plant for any sampling date, plan to apply a rootworm soil insecticide in 1981. If populations range from 1/2 to 1 beetle per plant, the probability of economic damage the following year is low, and a soil insecticide will probably not be necessary. If populations do not exceed 1/2 beetle per plant for any sampling date, a soil insecticide will not be needed the fol- lowing season. BLACK CUTWORMS Cutworm infestations, although extremely damaging in some regions in 1979, were not as widespread as during 1978. The unpredictability of cutworm outbreaks makes it impossible to forecast what the situation might be in 1980. Cutworm damage that necessitates replanting or a "rescue" treatment occurs on an average of 300,000 acres of corn annually, or on about 3 percent of the corn acreage, based on reports from county Extension advisers over the past 25 years. Damage estimates have ranged from a low of 30,000 acres in 1957 to a high of 1.9-million acres in 1978. The amount of damage prevented by applying soil insec- ticides at or before planting has not been determined. The factors that tend to favor cutworm outbreaks in- clude late planting, infestations of broadleaf weeds prior to planting, reduced tillage, and corn following soybeans. The most important factors may be late planting and pre- plant weed infestations. Fields that are planted late are more likely to develop a preplant weed infestation, and late-planted fields with weeds are more attractive to cut- worm moths as a site on which to deposit their eggs than fields tilled early in the spring. Fields with combinations of those factors are likely candidates for damage and should be monitored closely as the corn emerges. Currently, three options are available for cutworm con- trol: preplant or planting-time applications of soil insec- ticides to prevent damage and rescue treatments after the infestation appears. All have limitations. Because of the uncertainty in predicting which fields will have light, moderate, or heavy infestations of cut- worms, it may be more feasible to use rescue treatments for cutworm outbreaks rather than to use a preplant or planting-time treatment unnecessarily. Based on the relatively low incidence of cutworm prob- lems over the past 25 years, a grower may find an eco- nomic advantage to the wait-and-see system, which in- volves field scouting rather than a costly always-apply program in which the soil insecticide is routinely applied at or before planting for a problem that does not exist. Rescue (or emergency) treatments to control outbreaks of cutworms include sprays of chlorpyrifos (Lorsban), carbaryl (Sevin), or trichlorfon (Dylox), or carbaryl pel- letized bait. Broadcast the pelletized bait on the surface, but do not incorporate. Chlorpyrifos sprays should also be broadcast. Sprays of carbaryl may be banded over the row or broadcast, but the rates per acre need to be in- creased if the sprays are broadcast. Trichlorfon sprays should be banded. The keys to effective cutworm control with the rescue treatments are the amount of surface moisture and the movement of the worms. Control may be poor, regardless of the insecticide used, if the topsoil is dry and crusted and the worms are working below the soil surface. Cut- worm control under hot, dry soil conditions may be en- hanced by cultivating or running a rotary hoe over the field soon after spraying. This disruption may cause the worms to move around and come into contact with the insecticide. To determine the need for rescue treatments, scout the fields during plant emergence, particularly those fields con- sidered to be high-risk. Early detection of leaf-feeding or of cutting by cutworms is vital. When the corn plants are beginning to emerge, check the fields for leaf -feeding, cut- ting, wilting, or missing plants. Small cutworm larvae (less than 1/2 inch) feed on the leaves and do not begin cutting plants until they are about half grown. A control measure is needed on corn in the 2-leaf stage if 3 percent or more of the plants are cut and if there are 2 or more cutworms per 100 plants. At the 4-leaf stage, control is justified if 3 percent or more of the plants are cut and if there are 4 or more worms per 100 plants. A single cutworm will cut fewer of the 4-leaf plants than those in the 2-leaf stage. Preplant and planting-time treatments of chlorpyrifos (Lorsban) are registered for the control of black cut- worms. Some growers may want to use chlorpyrifos in their high-risk fields. The label for chlorpyrifos (Lorsban 15G) indicates that it "will control moderate to low infes- tations of cutworms." Research indicates that a planting- time treatment of chlorpyrifos (Lorsban 15G) is rela- tively effective in controlling light to moderate infestations of cutworms, but control may be unsatisfactory with heavy infestations. Although ethoprop (Mocap) is also regis- tered for control of cutworms, chlorpyrifos (Lorsban) has given better cutworm control in research trials. A preplant broadcast treatment of chlorpyrifos (Lors- ban 4E) is registered for cutworm control at 2 to 4 pints per acre. The insecticide should be incorporated into the top 2 to 4 inches of soil immediately after application. Re- search data are limited on the effectiveness of this treat- ment. The higher rate of 4 pints per acre is suggested. feeding by corn borer larvae from mid- June to early July. The fields with the tallest corn are the most attractive for egg laying by first-brood moths. Control is warranted if 50 percent or more of the plants have fresh whorl- feeding, if live borers are present, and if plants are 24 or more inches tall (with the leaves extended). First-generation borers reduce yields by stalk-tunnel- ing, which weakens the plant and destroys the tissue used to transport food within the plant. Some hybrids have varying degrees of tolerance or resistance to leaf-feeding by first-generation borers. Con- sider this trait when selecting varieties for 1980. Corn planted late is most attractive to moths laying eggs for the second generation. Fields should be moni- tored from mid- July to mid-August for egg masses or newly hatched larvae of the second brood. Yield losses from this brood are due to stalk breakage (physical dam- age) as well as to physiological damage. PLANTER-BOX SEED TREATMENTS A planter-box seed treatment with diazinon will pro- tect germinating corn against attack by seed-corn beetles and maggots. Use a seed treatment in fields that do not receive a soil insecticide at planting time, or use it when carbofuran (Furadan) is applied at planting time. The di- azinon planter-box seed treatment is not needed if terbufos (Counter), fonofos (Dyfonate), chlorpyrifos (Lorsban), ethoprop (Mocap), or phorate (Thimet) is applied at planting. NOTE: Excess dust from the seed treater may interfere with the electronic monitor in air planters. Use a diazinon seed-protectant to prevent damage to germinating soybeans from seed-corn maggots. Follow the label directions for application. The potential for damage is greatest during cool, wet springs when germination is slow. EUROPEAN CORN BORERS Overwintering larval populations in the fall of 1979 were substantially below those in the fall of 1978. Al- though the potential for first-generation infestations in 1980 appears to be lower, the most important factor rela- tive to damage will be the weather conditions in June, when the corn borer moths are emerging and laying eggs. Corn borer moths begin to emerge in late May in southern Illinois and mid- to late June in the central and northern regions. The females lay most of their eggs in the evening. They spend the daylight hours in fence rows and other protected areas. The eggs, which are laid in masses, are usually de- posited near the midrib on the underside of the lower corn leaves. Calm nights favor egg deposition by the moths. The absence of hard, beating rains during moth emergence also increases the potential for infestations. Corn that is planted early (the fields with the tallest corn) should be monitored closely for signs of whorl - REDUCED TILLAGE AND NO TILL PEST PROBLEMS Concern about insects should not keep you from adopt- ing conservation tillage practices. Most corn soil-insect problems that might be present in no-till or conservation tillage programs can be controlled with a soil insecticide applied at planting. Outbreaks of aboveground foliage- feeding pests, with a few exceptions, can be controlled with properly timed sprays. Close monitoring of fields to detect insect outbreaks is very important. Insect problems occur more frequently in no-till corn than in any other tillage program and are often more serious. No-till gives pests a stable environment for sur- vival and development. Soil insecticides may be needed on no-till corn follow- ing grass sod or in any rotation in which grasses and weeds are prevalent. Phorate (Thimet), fonofos (Dyfo- nate), terbufos (Counter), ethoprop (Mocap), and carbo- furan (Furadan) will provide some control of wireworms and white grubs in no-till corn planted in grass sod. FORAGE INSECTS In 1980, we expect alfalfa weevils to cause moderate to severe damage to the first cutting of alfalfa in most areas of Illinois. Only light to moderate damage is ex- pected in the east-central and northeastern sections. In southern Illinois, where much fall egg laying takes place, alfalfa- weevil larval damage occurs early in the spring. Damage to the first cutting in northern Illinois is more likely to occur if hay harvest is delayed, as in 1978 and 1979. Alfalfa- weevil larvae and adults also may cause dam- age to alfalfa stubble after the first hay crop is removed. Growers should inspect alfalfa fields closely during April, May, and June. Follow the suggestions in Circular 1136, Alfalfa Weevil Pest Management Program, to de- termine the need and proper timing of a treatment. A fungal disease organism, Entomophthora phytonomi, was found infecting alfalfa weevil larvae in Illinois for the first time in 1979. It occurred statewide, but its effect on the weevil population was not fully determined. In many fields, alfalfa- weevil numbers reached damaging levels before the disease killed the larvae. The fungus overwinters in Illinois as resting spores, so it should be present in alfalfa fields in 1980. Alfalfa- weevil populations may be kept below economic levels in some fields if the fungus germinates and spreads early enough in the spring. Check for brownish larvae stuck to the top leaves of the alfalfa plants. If the disease is prevalent and keeps up with the weevil population, con- trol measures may not be necessary. Potato leafhoppers may cause moderate to severe dam- age to the second and third cuttings of alfalfa in all areas of Illinois in 1980. Damage first appears as a yellow wedge-shaped area at the tip of the leaf and is more evi- dent during dry weather. Population levels are difficult to predict, however, because the leafhoppers do not survive the winter in Illinois. They migrate from states to the south into Illinois during May and June. Potato-leafhopper damage may begin on the new growth as soon as the first hay crop is removed. (Stunt- ing and yellowing are a sign of leaf hopper injury.) A swarm of leafhoppers at the time of the first cutting indi- cates that there may be problems in the new growth. If you use a sweep net to monitor fields, apply treatments when there are one or more leafhoppers per sweep. PEST-MANAGEMENT SCOUTING PROGRAMS In recent years, "pest-scouting" programs have been initiated by several pest-management consulting firms to serve growers. Scouts monitor fields for outbreaks of pests and keep a close watch on potential problems. Identifying and controlling pest outbreaks through scouting programs could save a farmer thousands of dollars. The scout's ob- servations can also be used to determine the need for ap- plying a rootworm soil insecticide the following year. Table 3. FIELD CORN Insect Time of attack Insecticide" Pounds of active ingredient per acre Placement Timing of application (See Table 10) Corn rootworm June-August terbufos (Counter) fonofos (Dyfonate)** carbofuran (Furadan)** chlorpyrifos (Lorsban) ethoprop (Mocap)** phorate (Thimet) lb lb lb lb lb lb 7-inch band Apply ahead of planter press wheel. See dis- cussion on page 4. Basal treatments during cultivation with Furadan, Dyfonate, Thimet, Counter, or Mocap are effective in late May or early June. Seed-corn beetle At germination diazinon tyz oz. a.i. per bu. On seed Or apply a band treatment of Dyfonate or Thimet. Seed-corn maggot At germination diazinon lVi oz. a.i. per bu. On seed Or apply Counter in the furrow, or band treatments of Dyfonate. Wireworm May-June terbufos (Counter) fonofos (Dyfonate)** cart ofuran ( Furadan) ethoprop (Mocap)** phorate (Thimet) lb 4 2b lb lb Furrow, Band Broadcast Furrow 7-inch band 7-inch band If infestations are severe, control may not be satisfactory. Thimet is labeled for the reduction of wireworms. Sod webworm May- June toxaphene At base of plant At time of initial attack. Cutworms May- June chlorpyrifos (Lorsban granules) chlorpyrifos (Lorsban spray) chlorpyrifos (Lorsban spray) carbaryl (Sevin bait) carbaryl (Sevin spray) trichlorfon (Dylox, Proxol spray) lb 2 \Vi 1-2 2b 1" 7-inch band Broadcast Broadcast Broadcast Plant base Plant base J Apply at planting. Controls moderate to low infestations. Preplant incorporated. Apply as a postplant rescue treatment when damage appears. See next page for footnotes. Table 3. FIELD CORN (continued) Insect Time of attack Insecticide" Pounds of active ingredient per acre Placement Timing of application (See Table 10) White grub Grape colaspis May-October May- June terbufos (Counter) 7-inch band Counter is labeled for the reduction of white grubs. The insecticides suggested for wire- worms will give partial control of white grubs and grape colaspis but are not regis- tered for these pests. Garden symphylan May-July terbufos (Counter) fonofos (Dyfonate)** 1-2* 2 Band Broadcast Before planting, lightly incorporate. Grasshopper June- September carbaryl (Sevin) diazinon dimethoate (Cygon) 1-lVi Vi Over row as spray As needed. For ensilage corn use Sevin or diazinon. Flea beetle May-June carbaryl (Sevin, Savit) diazinon 1 Over row as spray When damage becomes apparent on small corn. Army worm May-August carbaryl (tSevin) trichlorfon (Dylox, Proxol) methomyl (*Lannate sprayc) 1 Over row as spray Fall armyworm July-September carbaryl (Sevin, Savit) sprays diazinon granules trichlorfon (Dylox spray) methomyl (*Lannate spray') H/2 1 1 In whorls At first migration or when leaves below car level are consumed and worms are eating leaves above ear level. Granules preferred when worms deep in whorl. If worms are small and out on leaves, sprays are effective. Chinch bug June-August carbaryl (fSevin) 2 Spray at base of plant At start of migration from small grains. Thrips June malathion On foliage as spray When severe wilting and discoloration are noticed. Japanese beetle July-August carbaryl (Sevin, Savit) Over plant During the silking period to protect pollina- tion. Corn leaf aphid July-August malathion diazinon Foliage spray Apply during late whorl to early tassel when 50% of the plants have light to moderate infestations. Corn rootworm adults Late July, early August carbaryl (Sevin, Savit) malathion diazinon phosmet (Imidan) Overall spray Before 75% of plants have silked, if there or directed are more than 5 beetles per ear and if silk toward silk clipping is observed. Only to protect pollina- tion. Corn borer, June- July carbaryl (Sevin first generation granules) diazinon granules carbofuran (Furadan granules) fonofos (Dyfonate granules) Vz On upper i/$ When 50% or more plants show fresh whorl of plant and feeding, live borers are present, and plants into whorl are over 24" tall. Corn borer, Mid- August second generation carbaryl (Sevin granules) diazinon granules carbofuran (Furadan granules) fonofos (Dyfonate granules) Vz Over row Apply at first hatch when there are 100 or more egg masses per 100 plants. Two treat- ments may be necessary because of the ex- tended egg-laying period. Southwestern corn borer August carbofuran (Furadan granules) From ear Direct granules into whorls. Apply when upward 25% of plants have egg masses or larvae on leaves. Early-planted corn usually escapes damage. * Use restricted to certified applicators only, f State-labelled insecticide. Applicator must have Illinois label in possession when applying. ** Liquid formulations are restricted. " See Table 10 for insecticide restrictions. b Based on 40-inch row spacing. Increase rates for narrow rows. c To be applied only by experienced operators or those wearing protective clothing. Table 4. STORED GRAIN (Corn, Wheat, and Oats)8 Insect Time of attack Insecticide and dilution Dosage Placement Suggestions (See Table 10) Angoumois grain moth (earcorn) April-October (southern 1/3 of Illinois only) malathion 57% E.C., 3 oz. per gal. water Apply te runoff Spray surface and sides May 1 and August 1 Plant tight husk varieties. Store as shelled corn to avoid all but surface damage by angoumois moth. Meal moths and surface infesta- tions onlyb April-October dichlorvos 20% (DDVP, Vapona) plastic resin strip0 1 per 1,000 cu. ft. space above grain mass General Internal and ex- ternal feeders Rice and granary weevils Flat grain beetle Saw-toothed grain beetle Rusty grain beetle Foreign grain beetle Cadelle beetle Flour beetle April-October malathion 57% E.C., 1 pt. per 3-5 gal. waterd 3-5 gal. per 1,000 bu. Attach to Clean and spray bin with 1.5% malathion to ceiling or runoff before storage. Store only clean dry side wall grain. Install May 15 or at storage or for emergency control. Replace every 6 weeks between May and October. Spray Clean and spray bin with 1.5% malathion to uniformly as runoff before storage. Store only clean dry grain is grain. Protect surface with dichlorvos resin binned strips as recommended for meal moths. liquid fumigant* 3-5 gal. per 1,000 bu. On surface; repeat if nec- essary *methyl bromide + ♦ethylene dibromide*1 g As directed On surface Clean and spray bin with 1.5% malathion to runoff before storage. Store only clean dry grain. Apply in late July and September in the southern half of Illinois; apply in mid- August in the northern half of Illinois. Pro- tect surface with dichlorvos resin strips as recommended for meal moths. ♦aluminum phosphideh 180 tablets or 300 pellets per 1,000 bu. Uniformly Fumigants are best used for emergency con- throughout trol of existing infestations. * Use restricted to certified applicators only. 'Corn need not be treated if harvested after October 1 unless it is to be carried over the following summer. Wheat and oats should be treated if they are to be held for one month or more in storage after harvest. Soybeans stored at safe moisture levels are attracted only by Indian meal moth. b Remove webbing before treatment. 0 Effective only in enclosed bins. Kills adult moths but not the eggs or larvae. Several weeks required to control effectively an existing in- festation. Fumigate the grain if immediate control is desired. Also cleared for use in bins of stored soybeans. d Use only the grade of malathion labeled for use on stored grain. Apply after drying because malathion vaporizes and is lost rapidly when grain is heat-dried. e Some common liquid fumigants are : *carbon bisulfide + *carbon tetrachloride, ^ethylene dichloride + *carbon tetrachloride, *ethylene dichloride + *ethylene dibromide + *carbon tetrachloride, etc. f Use with extreme caution. Apply only under calm conditions and when grain temperature is 70° F. or above. Grain should be 8 inches below the lip of the bin and should be leveled before fumigating. Cover the surface with a plastic tarp for 24 hours, then air out. g Called the 73 mixture. h Called *Phostoxin or Detia. Slow vaporization with a 3-day exposure period. Can be used at grain temperature of 60° F. or above. Grain should be 8 inches below the lip of the bin and should be leveled before fumigating. Cover the surface with a plastic tarp for 3 days, then air out. Table 5. SMALL GRAINS (Barley, Oats, Rye, Wheat) Insect Time of attack Insecticide* Pounds of active ingredient per acre Placement Timing of application (See Table 10) Armyworm May-June toxaphene" trichlorfon (Dylox) I1/2 On foliage When there are 6 or more armyworms per linear foot of row and before extensive head- cutting occurs. Do not use Dylox on rye. Greenbug English grain aphid May-June Cygon methyl parathion (Penncap-M)* malathion l On foliage When needed. Penncap-M is cleared for greenbug only. Use Cygon and Penncap-M on wheat only. * Use restricted to certified applicators only. 8 See Table 10 for insecticide restrictions. b For use on dairy farms only when alternate material is not available and when insect emergency exists. Do not apply as foliage sprays or dusts to or adjacent to dairy pasture, hay, or forage crops. Table 6. ALFALFA AND CLOVER Pounds of active Time of ingredient Timing of application6 Insect attack Insecticide*' b per acre Placement (See Table 10) Alfalfa weevil (Spring treatment) March-June carbofuran (Furadane> d)* 14 azinphosmethyl (Guthion0)* Vz methyl parathion0* Vz methidathion (Supracidec) Vz malathion plus methoxychlor diazinon plus Vz methoxychlor (Alfatox) 1 phosmet (Imidan) methyl parathion* (Penncap-M)' 1 Vz On foliage Refer to Circular 1136. Or, when 25% of the tips are being skeletonized and there are 3 or more larvae per stem, treat immediately; two treatments may be necessary on first cutting; regrowth following first cutting may need protection. By ground, use a minimum of 20 gal. of finished spray per acre (10 gal. on stubble) or 4 gal. by air. Do not apply during bloom. Instead, cut and remove the hay. Do not spray alfalfa with Penncap-M during bloom to avoid injury to bees. Clover leaf weevil March-April malathion 1 On foliage When larvae are numerous and damage is noticeable, usually early to mid-April. Spittlebug Late April, early May azinphosmethyl (Guthion0)* V2 malathion 1 On foliage When spittle masses are found and nymphs average over 1 per stem. Aphid April-May dimethoate (Cygon, De-Fend) diazinon malathion Vz Vz 1 On foliage When aphids are becoming abundant and lady beetle larvae and adults, parasites, and disease are slight. Leaf hopper June- August carbaryl (Sevin, Savit) 1 diazinon Vz dimethoate (Cygon, Vz De-Fend) trichlorfon (Dylox) Y\ On foliage When second-growth alfalfa is 4 to 6 inches high, or as needed. If using a sweep net to monitor, apply treatment when there are one or more leaf hoppers per sweep. methidathion (Supracide0) Vz Webworm July-August carbaryl (Sevin, Savit) trichlorfon (Dylox) 1 1 On foliage When damage appears. Variegated cutworm April-June carbaryl (Sevin bait) trichlorfon (Dylox) methomyl (Lannate)* IV2 1 Vz On foliage Cut, remove hay, and spray immediately. Army worm May-June, September carbaryl (Sevin) trichlorfon (Dylox) \Vi 1 On foliage Only when grasses are abundant. Grasshopper June-September dimethoate (Cygon, Vz De-Fend) carbaryl (Sevin, Savit) 1 diazinon Vz carbofuran (Furadan0- d)* V\ On foliage When grasshoppers are small and before damage is severe. When plants are blooming, do not apply Sevin or Cygon. Apply others only late in day. * Use restricted to certified applicators only. ■ See Table 10 for insecticide restrictions. b Before applying insecticides, be certain to clean all herbicides out of equipment. During pollination, apply very late in day or, if possible, avoid application during bloom. 0 To be applied only by experienced operators or those wearing protective clothing. d Only for pure stands of alfalfa. When using no more than V\ pound per acre, allow 7 days between application and harvest. If you use Va to Vz pound per acre, allow 14 days to elapse between application and harvest. e This product is highly toxic to bees exposed to direct treatment or residues on crops. Table 7. NONCROP AREAS Insect Time of attack Insecticide" Pounds of active ingredient per acre Placement Timing of application (See Table 10) Grasshoppers June- July carbaryl (Sevin 4-Oil) 1 carbaryl (Sevin) 1 dimethoate (fCygon) Vz diazinon Vz On foliage When nymphs are abundant and before mi- gration into row crops. Treat while hoppers are small. * See Table 10 for insecticide restrictions, t State-labelled insecticide. Applicator must have Illinois label in possession when applying. Table 8. GRAIN SORGHUM Insect Time of attack Insecticide" Pounds of active ingredient per acre Placement Timing of application (See Table 10) Webworm After heads form carbaryl (Sevin, Savit) lVz On grain When 10 to 25 percent of the heads are in- head fested with 5 or more larvae per head. Pest usually bad in wet seasons on late-planted grain. Corn earworm After heads form carbaryl (Sevin, Savit) m Direct at head or broadcast When there is an average of 2 worms per head. Midge August- September dimethoate (Cygon) diazinon carbaryl (Sevin) Va Direct at head When 50% of heads have begun to bloom and there are 1 or more midge adults per head. Corn leaf aphids All season dimethoate (Cygon) malathion Va 1 Broadcast Under drouth conditions when populations are heavy and damage is apparent. Greenbug June-July dimethoate (Cygon, De-Fend) malathion Va l Broadcast When greenbug damage is sufficient to cause death of more than 2 normal-sized leaves be- fore the hard-dough stage. Fall armyworm July-August carbaryl (Sevin) 1*5 Over row When there is an average of 2 worms per head. Whorl feeding is seldom economic. * See Table 10 for insecticide restrictions. Table 9. SOYBEANS Insect Time of attack Insecticide" Pounds of active ingredient per acre Placement Timing of application (See Table 10) Seedcorn maggot Germination diazinon 3A oz. a.i. per bu. On seed At planting time. Bean leaf beetle May-June, August carbaryl" (Sevin, Savit) acephate (Orthene) 1 On foliage When leaf feeding exceeds 35% prebloom and 15% between blooming and pod fill. Grasshopper June-September dimethoate (Cygon) carbarylb (Sevin, Savit) carbaryl (fSevin 4-Oil) Vl 1 1 On foliage When migration from adjacent crops begins. Green clover worm August carbarylb (Sevin) 1 methomyl (Lannate0)* Va Bacillus thuringiensis (See label) (Dipel, Thuricide) carbaryl (fSevin 4-Oil) 1 On foliage When damage occurs between blooming and pod fill. Usually requires 12 or more half- grown worms per foot of row and 15% de- foliation to justify treatment. Webworm June-August carbarylb (Sevin, Savit) 1 Usually requires 15% or more defoliation be- tween blooming and pod-fill to justify treat- ment. Mites June-August carbophenothion (Trithion') dimethoate (Cygon) On foliage As needed on field margins and entire field. Stink bugs July and August acephate (Orthene) Va On foliage As needed when bugs are numerous; 1 per yard of row may cause damage. Thrips June-August carbarylb (Sevin, Savit) 1 On foliage As needed. * Use restricted to certified applicators only, f State-labelled insecticide. Applicator must a See Table 10 for insecticide restrictions on soybeans. b Sevin should not be used at more than 1 lb. per acre. Higher rates may damage plants. ' To be applied only by experienced operators or those wearing protective clothing. have Illinois label in possession when applying. 10 Table 10. LIMITATIONS IN DAYS BETWEEN APPLICATION OF THE INSECTICIDE AND HARVEST OF THE CROP AND OTHER RESTRICTIONS ON THE USE OF INSECTICIDES FOR FIELD CROP INSECT CONTROL (Blanks in the table denote that the material is not suggested for that specific use in Illinois) Worker re-entry times" (hours) Field corn Sorghum Forage crops Seed and soil Grain Ensilage and stover Alfalfa Clover Pasture Counter (terbufos) De-Fend, Cygon (dimethoate) diazinon ... A A 14 14 0 28 7 10.B 7 7 "o **Dyfonate (fonofos)b Dylox, Proxol (trichlorfon) **Furadan (carbofuran)" ♦Guthion (azinphosmethyl),,b 24 A A 45 C 45 C D 0 7,E 16.B 0 16,B 6 Imidan (phosmet) *Lannate (methomyl)ab Lorsban (chlorpyrifos) malathion A 14 0 50 5 14 3 50 5 "l 7,B 7 0 0 0 methoxychlor ♦methyl parathiona,b **Mocap (ethoprop)b *Penncap-Ma'b'c Sevin, Savit (carbaryl) 48 A 0,K o,k 21 7 15 15 0 7 15 0 0 Supracideb (methidathion) Thimet (phorate) toxaphene A 30,H 28,A 30,H I ... 10,G Barley Oats Rye Wheat Soybeans Cygon (dimethoate) Thuricide, Dipel (Bacillus thuringiensis) Dylox (trichlorfon) *Guthion (azinphosmethyl)ab 24 21 21 60 21 21 0 45,F *Lannate (methomyl)a'b malathion *Penncap-Ma,b'c Sevin (carbaryl) "l 15 14 0 toxaphene Trithion (carbophenothion)a,b Orthene (acephate) 48 J J J J 7,F 14,F * Use restricted to certified applicators only. ** Liquid formulations are restricted. " Workers should be warned in advance of treatments. Workers may not enter fields treated with the insecticides without wearing protective clothing for the intervals indicated. They may not enter a field treated with other insecticides until the spray has dried or the dust has settled without wearing protective clothing. Protective clothing includes a hat, long-sleeved shirt, long-legged pants, and shoes and socks. b Sprays to be applied only by experienced operators wearing proper protective clothing. 0 Microencapsulated. A. No specific restriction when used as recommended. B. Apply only once per cutting, and do not apply during bloom. C. Three applications may be made per season. Can be applied up to harvest. D. Do not make a foliar application if Furadan 10 granules were applied at more than 10 pounds per acre at planting. Do not make more than two foliar applications per season. E. Make no more than one application per season. F. Do not graze or feed treated vines to livestock. G. Make no more than one foliage and one stubble application per cutting. H. Besides treatment at planting, one more application can be made at cultivation or over the corn later in the season. I. Do not feed treated forage to dairy animals. Do not feed sprayed forage or granular-treated corn silage to livestock fattening for slaughter. Do not graze meat animals on gran- ular-treated stover within 28 days of slaughter. J. Do not graze or feed treated forage to dairy animals or to ani- mals being finished for slaughter. K. Do not apply granules within 7 days of harvest. ALWAYS CONSULT PESTICIDE LABEL FOR MORE INFORMATION 11 PESTICIDE SAFETY Certain precautionary steps should be taken when han- dling insecticides. Some of the insecticides suggested in this publication can be poisonous to the applicator. The farmer is expected to protect himself, his workers, and his family from needless exposure. When using insecticides, apply all the scientific knowl- edge available to make sure that there will be no illegal residue on the marketed crop. Such knowledge is con- densed on the label. READ THE LABEL CAREFULLY AND FOLLOW THE INSTRUCTIONS. The label should be recent and not from a container several years old. Do not exceed the maximum rates suggested. Observe the interval between application and harvest. Apply only to crops for which use has been approved. Make a record of the product used, the trade name, the percentage con- tent of the insecticide, the dilution, the rate of application per acre, and the date or dates of application. Always handle insecticides with respect. The persons most likely to suffer ill effects from insecticides are the applicator and his family. Accidents and careless, needless overexposure can be avoided. Following these rules will prevent most insecticide accidents : 1. Wear rubber gloves when handling insecticide con- centrates. 2. Do not smoke while handling or using insecticides. 3. Keep your face turned to one side when opening, pouring from, or emptying insecticide containers. 4. Leave unused insecticides in their original contain- ers with the labels on them. 5. Store insecticides out of the reach of children, irre- sponsible persons, or animals; store preferably in a locked building. Do not store near livestock feeds. Better yet, buy no more pesticide than you will use, thus eliminating a pesticide storage and disposal problem. 6. Triple rinse, bury, or burn all empty insecticide containers or take them to an appropriate sanitary landfill. 7. Do not put the water-supply hose directly into the spray tank or blow out clogged nozzles or spray lines with your mouth. 8. Wash with soap and water exposed parts of the body and clothes contaminated with insecticides. 9. Do not apply to fish-bearing or other waters. 10. Do not leave puddles of spray on impervious sur- faces or apply insecticides near dug wells or cisterns. 11. Do not apply insecticides, except in an emergency, to areas with abundant wildlife. 12. Do not spray or dust when weather favors drift. 13. To avoid bee kill, apply insecticides after bee activ- ity has been completed for the day; use the least toxic ma- terials. Warn beekeepers that you are applying insecticides. POLICY STATEMENT The Illinois Insect Pest Management Guide: Field and Forage Crops (Circular 899) is revised annually and is intended for use during the current calendar year only. Not all registered insecticides are included in this circular. Insecticides that are effective and do not present an undue hazard to the user are suggested whenever possible. Trade names have been used for simplicity, but their usage does not imply endorsement of one product over another, nor is discrimination intended against any product. This guide for insect control is based on research re- sults from the Illinois Natural History Survey, the Uni- versity of Illinois Agricultural Experiment Station, other experiment stations, and the U.S. Department of Agri- culture. Requested label clearances for a few uses of some in- secticides, carriers, and solvents are uncertain for 1980 because many requests have not yet been officially cleared. Be sure to check with your county Extension adviser in agriculture if you are in doubt about an insecticide you plan to use. We will make announcements of label changes through the news media to keep you up to date. REFERENCES This circular lists only suggested uses of insecticides for the control of many pests in Illinois field crops and is not designed to discuss other methods of control. Fact sheets discussing nonchemical control methods, descrip- tions of specific insects, and their life history and biology (designated by NHE numbers) can be obtained from the office of the county Extension adviser in agriculture or by writing to Entomology Extension, 172 Natural Resources Building, Urbana, IL 61801. The suggestions given in this circular are revised annually by entomologists of the College of Agriculture and the Illinois Natural History Survey. Issued in furtherance of Cooperative Extension Work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. JOHN B. CLAAR, Director, Cooperative Extension Service, University of Illinois at Urbana-Champaign. The Illinois Cooperative Extension Service provides equal op- portunities in programs and employment. 16M— 10-79— 45 8 80— PC W UNIVERSITY OF ILLINOIS-URBANA Q630.7IL6C C005 CIRCULAR URBANA, ILL 899 REV. 1980 0112 019541157