Pest Management (Janet Knodel and Larry Charlet) Integrated Pest Management Economic Injury Level Sunfl ower can be a high-risk crop because of potential and Economic Threshold Levels losses from diseases, insects, birds and weeds. These One major component of a pest management program potential risks require that growers follow integrated is determining when tactics should be implemented pest management (IPM) practices. IPM is a sus- to prevent economic loss. Economic loss results when tainable approach to managing pests by combining pest numbers increase to a point where they cause biological, cultural, physical and chemical tools in a crop losses that are greater than or equal to the cost of way that minimizes economic, health and environ- controlling the pest. An economic injury level (EIL) is mental risks to maintain pest populations below levels defi ned as the level of pests that will cause economic that cause unacceptable losses to crop quality or yield. damage. An EIL recognizes that treatment is justifi ed The concept of pest management is based on the fact for some pest population levels while others are not of that many factors interact to infl uence the abundance economic importance. of a pest. Control methods vary in effectiveness, but integration of these various population-regulating An economic threshold level (ETL) is the level or factors can minimize the number of pests in sunfl ower number of pests at which tactics must be applied to and reduce the cost of managing pest populations prevent an increasing pest population from causing without unnecessary crop losses. IPM also recom- economic losses. Usually the ETL is lower than the mends the judicious use of chemical pesticides when EIL. The ETL has been defi ned most extensively for needed and suggests ways to maximize effectiveness insect pests; fewer ETLs have been established for and minimize impact on nontarget organisms and the other types of pests. The ETL varies signifi cantly environment. among different pests and also can vary during differ- ent developmental stages of the crop. Crop price, yield potential, crop density, cost of control and environ- mental conditions infl uence the ETL and EIL. Gener- ally, the ETL increases as cost of control increases and decreases as the crop value increases. Monitoring Pest Population Levels In general, fi elds should be evaluated regularly to de- termine pest population levels. A weekly fi eld check is usually suffi cient, but fi eld checks should be increased to two or three times a week if the number of pests is increasing rapidly or if the number is approaching an economic threshold level. Pests should be identifi ed accurately because economic threshold levels and con- 26 trol measures vary for different organisms. In addition, Summary when insects pests are monitored, many insects are Growers should examine their operations and benefi cial and may help reduce numbers of injurious minimize pest damage by adopting integrated pest insects; recognizing which are pests and those that are management practices based on the use of eco- benefi cial is important. nomic threshold levels, when available, plus carefully Management Pest monitoring and combining various control methods. Tools of Pest Management Signifi cant progress with sunfl ower pest management Tools of pest management include many tactics, of has been made and undoubtedly will continue to be which pesticides are only one. These tactics can be made in the future to aid successful sunfl ower produc- combined to create conditions that are the least condu- tion. The following sections provide current informa- cive for pest survival. Chemical or biological pesti- tion on management of insects, diseases, weeds, birds cides are used when pests exceed economic threshold and other sunfl ower pests. A growing season calendar levels; sometimes they are necessary when control is shows the major sunfl ower pest problems and time of needed quickly to prevent economic losses. occurrence in the northern Great Plains production area (Figure 16). Some of the tools or components of pest management that can be used to reduce pest populations are: Biological Controls Benefi cial insects Benefi cial pathogens Host Resistance Cultural Controls Planting and harvest dates Crop rotation Tillage practices Mechanical/Physical Controls Temperature Weather events Trapping Chemical Controls Pesticides Attractants Repellents Pheromones ■ Figure 16. A growing season calendar indicating time of occurrence of major sunfl ower pests. (J. Knodel) 27 Quick Reference Guide to Major Sunfl ower Insects The information presented on this page is designed to be a quick reference for growers, crop consultants, fi eld scouts and others. Since this information is very brief, the user should refer to the following pages for more detailed data on life cycles, damage, descriptions, etc. Insects Description Occurrence, Injury and Economic Threshold (ET) Cutworms Dirty gray to gray brown. ET – 1 per square foot or 25 percent to 30 percent stand (several species) Grublike larva, 0.25 to 1.5 inches in length. reduction. Appear in early spring when plants are in the seedling stage, chewing them at or slightly above ground. Palestriped Adult: 1/8 inch long and shiny black, with two white ET – 20 percent of the seedling stand is injured and at risk Flea Beetle stripes on the back. The hind legs are enlarged and to loss due to palestriped fl ea beetle feeding. Scout for modifi ed for jumping. fl ea beetles by visually estimating population on seedlings or using yellow sticky cards placed close to the ground. Sunfl ower Beetle Adult: reddish-brown head, cream back with three ET – 1 to 2/seedling (adults), or 10 to 15/seedling dark stripes on each wing cover. Body 0.25 to 0.5 (larvae). Adults appear in early June, larvae shortly inch long. Larva: yellowish green, humpbacked in thereafter. Both adults and larvae chew large holes appearance, 0.35 inch in length. in leaves. Sunfl ower Adult: wingspread 0.63 to 0.75 inch, gray brown ET – none. First generation adults appear in late May to Bud Moth with two dark transverse bands on forewings. mid-June. Second generation adults appear in midsummer. Larva: Cream-colored body (0.33 to 0.4 inch) with Larvae from fi rst generation damage terminals and stalks, a brown head. whereas second generation larvae feed in receptacle area. Longhorned Adult: pale gray and 5/8 inch (6 to 11 mm) in No scouting method or ET has been developed. Adults are Beetle (Dectes) length, with long gray and black banded antennae. present from late June through August. Larvae tunnel and Larvae: yellowish with fl eshy protuberances on the feed in the petioles and stem pith and girdle the base of fi rst seven abdominal segments (1/3 to 1/2 inch) plants. Stalks often break at the point of larval girdling. Sunfl ower Stem Adult: small (0.19 inch long) weevil with a ET – 1 adult/3 plants in late June to early July. Adults Weevil gray-brown background and white dots on the back. appear in mid to late June, with larvae in stalks from early July to late summer. Thistle Caterpillar Adult: wingspread of 2 inches, upper wing surface brown ET – 25 percent defoliation, provided that most of the (Painted Lady with red and orange mottling and white and black spots. larvae still are less than 1.25 inches in length. Adults Butterfl y) Larva: brown to black, spiny, with a pale yellow stripe appear in early to mid-June, with larvae appearing on each side, 1.25 to 1.5 inches in length. shortly thereafter. Larvae chew holes in leaves. Sunfl ower Midge Adult: small (0.07 inch), tan, gnatlike insect. ET – none. Adult emergence begins in early July. Larvae Larva: cream or yellowish, 0.09 inch long, tapered at feed around head margin and at the base of the seeds, front and rear. causing shrinkage and distortion of heads. Sunfl ower Seed Adults: the red sunfl ower seed weevil is about 0.12 ET – generally 8 to 14 adult red sunfl ower weevils per head Weevils inch long and rusty in color. The gray sunfl ower seed (oil) and one per head (confectionery). Adults appear in weevil is about 0.14 inch long and gray in color. late June to early July. Treat for red sunfl ower seed weevil Larvae: both species are cream-colored, legless and at R5.1 to R5.4. Larvae feed in seeds from mid to late C-shaped. summer. Sunfl ower Moth Adult: body is 0.38 inch long, with 0.75 inch ET – 1 to 2 adults/5 plants at onset of bloom. Adults are wingspread. Color is buff to gray. Larva: brown head migratory and usually appear in early to mid-July. Larvae capsule with alternate dark and light lines running tunnel in seeds from late July to late August. longitudinally, 0.75 inch in length. Banded Sunfl ower Adult: small 0.25-inch straw-colored moth with brown ET – See banded sunfl ower moth section for egg or adult Moth triangular area on forewing. Larva: in early growth sampling methods for determining ET. Sampling should be stage, off-white, changing to red and then green color conducted in the late bud stage (R-3), usually during mid- at maturity, 0.44 inch in length. July. Adults appear about mid-July to mid-August. Larvae present in heads from mid-July to mid-September. Lygus Bug Adult: small (0.2 inch in length), cryptically colored ET - for CONFECTION SUNFLOWERS ONLY – insects with a distinctive yellow triangle or “V” on 1 Lygus bug per 9 heads. Two insecticide sprays are the wings and vary in color from pale green to dark recommended: one application at the onset of pollen shed brown.