Crop Protection Research Institute

The Benefits of Insecticide Use: Sweet Peppers

Pepper Maggot Adult Misshapen Green Bell Pepper, Possible Damage from Pepper Weevils

Pepper Weevil Larvae Damage European Corn Borer Damage

March 2009

Leonard Gianessi

CropLife Foundation 1156 15th Street, NW #400 Washington, DC 20005 Phone 202-296-1585 www.croplifefoundation.org Fax 202-463-0474 Key Points

• The pepper maggot feeds only on solanaceous crops and has damaged up to 90% of unsprayed pepper crops. • In the early 1900s the pepper weevil caused a 33% loss in the U.S. commercial pepper crop in the U.S. • Sprays for European corn borer control increased pepper yields by 2 to 4 tons per acre. • A near zero tolerance exists for peppers with a pepper weevil, pepper maggot, or European corn borer present.

Technical Summary

Growers in California and seven southern and north central states (Fl, GA, MI, NJ, NC, OH, TX) produce 1.7 billion pounds of sweet peppers with a value of $585 million on 66,000 acres annually. Insecticides are used on 85-100% of the pepper acres [21]. In Georgia, 10 insecticide applications are made to pepper acres annually [19]. The total cost of the pepper insecticide spray program in Georgia is estimated at $186 per acre out of a total cost of $8935 for producing an acre of peppers (2%) [20]. In Florida, New Jersey, and Michigan, the costs of insecticides are $322/A, $76/A, and $52/A respectively, representing 2-4% of the cost of producing sweet peppers [28]-[30].In California, insecticide costs are $120-$340/A[38][39].

Peppers originated in Mexico and Central America. Christopher Columbus encountered pepper in 1493 and because of its pungent fruit, thought it was related to black pepper which is actually a different plant genus. Nevertheless, the name stuck and he introduced the crop to Europe. Bell peppers are a member of the nightshade family and related to tomato, eggplant and potato.

Insects are a major concern in pepper production. Primary insect pests include pepper weevils, European corn borers, other caterpillar-type pests (armyworms, cutworms and loopers), thrips, aphids, flea beetles, potato psyllid, whiteflies, leafminers and pepper maggots. Caterpillar-type pests cause damage by their feeding on the foliage and fruiting structures and eat large holes anywhere on the fruit’s surface. Aphids and thrips devitalize plants with their feeding and also spread viruses. Broad mite feeding distorts plant tissue and leafminers reduce photosynthetic area of leaves. Many of the secondary and occasional pests of pepper are controlled as a result of broad-spectrum insecticide applications for key pests which include the pepper weevil in southern states and the European corn borer in mid-Atlantic and North Central states. Peppers are a high value crop with high standards for consumer appearance and quality. Entire fields of peppers have been abandoned because of holes caused by insect feeding .Without an efficacious insecticide for beet armyworm control it was estimated that 50% of the Texas crop could be lost [18].Organic pepper growers are permitted the use of BT, pyrethrin, azadirachtin , soaps, oils, and the Entrust formulation of spinosad for control of insects.

Pepper Weevil

Pepper weevil is apparently of Mexican origin and was first found in the U.S. in Texas in 1904, reaching California in 1923 and Florida in 1935. It is now found across the southernmost US from Florida to California. Pepper weevil populations persist only where food plants are available throughout the year, largely limiting its economic pest status to the southernmost states in the U.S. [27]. Pepper weevil larvae develop only on plants in the family Solanaceae.

The pepper weevil can complete its larval development in the fruit and/or flowers of most pepper varieties and on several species of nightshade. Infestations in North Carolina and farther north usually result when weevils are transported from infested areas on transplants [2]. The pepper weevil is not reported to successfully pass the winter in the Carolinas. Outbreaks of pepper weevils have occurred periodically in New Jersey causing large losses [7].

Adult pepper weevils feed on fruit and leaf buds and lay eggs on flowers, buds and fruit. Females may lay 100 to 300 eggs over a one-to two-month period. Females bore a little hole in developing fruit or flower buds. The hole is plugged with fecal matter (frass) after an egg is deposited. On flower buds, adult and larval feeding causes bud drop. Larvae (grubs) feed inside pepper pods. Larvae bore into pepper pods and feed for about ten days. The larvae migrate to the seed mass where they feed on the core and developing seeds. The most important damage is the destruction of blossom buds and immature pods. If fruit are small when infested, they may drop from the plant before maturing. Often, entire pepper fields must be plowed under because too few fruit are left to harvest, and the infestation poses a threat to later pepper plantings. Up to 90% fruit loss has been measured in experimental plots infested early in the season and left untreated [1]. Additionally, even moderate infestations late in the season can cause complete loss of fields. Larger fruit do not immediately drop when they become infested, and entire fields are often abandoned because of concern in shipping infested fruit to market [1]. The feeding of grubs within the pods causes the seeds and cores to turn black. Pods attacked late in the season may appear to be sound but show this blackened condition when opened. Subsequent discovery of infested fruit can jeopardize the marketability of an entire shipment [3]. Full-grown larvae construct cells of black frass within peppers and pupate. Four to six days later a new generation of weevils emerges. In Florida and Georgia, 5 to 8 generations occur each year.

In the early 1900s the pepper weevil caused a 33% loss in the commercial pepper crop for several consecutive years [4]. Many growers in Texas gave up the growing of peppers because of the pepper weevil-up to 30% of the plants were infested [32].Until DDT was available, there was no satisfactory chemical control. Calcium arsenate and cryolite were not completely effective [6]. In the 1930s, the pepper weevil caused losses of 50% of the California pepper crop [32].Even with partial control of pepper weevil with cryolite, the rate of return was $10 for every $1 spent on insecticides in California [33]. Calcium arsenate was objectionable because asrsenic was usually absorbed by the pod stems and could not be removed. DDT was found to be the most effective chemical (98% mortality) and was in common use beginning in 1945 [6]. In the 1930s it was concluded that without control of the pepper weevil, peppers could not be grown in Florida [32].

In tests in 1979 insecticides significantly reduced the number of pepper weevils found in dropped pods from 7500 per acre to as few as 200 per acre [5]. The spray threshold is to spray if one beetle is found in 200 plants. In commercial pepper fields in Texas, insecticide sprays for pepper weevil resulted in net returns of $13- $80 for every $1 spent on the spray[31].

Natural enemies have not been important in checking pepper weevil abundance, probably because its immature stages are well protected inside pepper pods [6]. Parasitoids of the pepper weevil provide up to 26% control [27]. Beauveria bassiana works well as a biological control of the pepper weevil, but this product is too expensive to use [34].

Insecticides are the most common tactic for control of pepper weevil in bell peppers because of their relative low cost and proven efficacy [25].

There are few cultural practices that significantly affect pepper weevil damage. Thirty- five pepper varieties were tested for resistance but few differences in susceptibility were found [27].

Following pepper harvest in Florida, the pepper weevil disperses to nightshade plants.In Florida, research has shown that a combined approach of removing nightshade and releasing parasites combined with insecticide spraying provided effective control of the pepper weevil [24].In California the weevil is commonly found throughout the year on a weed host, black nightshade. The pepper weevil is a common pest in Southern California.

European Corn Borer

The European corn borer has more than 200 host plants which include many common weeds and crops. Shortly following the first discovery, about 1917, of the European corn borer (ECB) in the U.S., several investigators mentioned that peppers were frequently attacked [8]. The ECB was first found on the Eastern shore of Virginia in 1931 [22]. Since about 1951, the European corn borer has been a serious economic pest in mid- Atlantic states (New Jersey, Maryland, Delaware, Virginia), Ohio and Michigan. In one pepper field in Nelsonia, Virginia an infestation of 99.5% was observed in 1951 [9]. Inspections of many pepper fields in the mid Atlantic region during the 1958 and 1959 seasons indicated an average loss to borer infestations of from 40% to 50% of the entire crop [10]. Many fields had 75% to 100% of the pepper fruits infested.

Biological studies have shown that egg-laying activity by the corn borer moths practically ceases after September 7. Consequently, peppers maturing in late September and October are virtually free of borers. Growers took advantage of this fact and as a result pepper production on the Eastern shore of Virginia was largely limited to fall peppers. This cultural practice was not entirely satisfactory for three reasons:1) peppers planted in July consistently had a poor set of fruit; 2) the production period of a relatively long-lived plant is limited by the late planting; and 3) there was an increased early season demand for peppers, both for processing and for fresh market consumption [22].Control of the borer became essential to continue growing peppers as a profitable crop in the region [10]. Experiments with DDT reduced infestations to below 1%. The difference in yield due to corn borer control was 2 to 4 tons per acre in favor of the spray treatment [11].

In Ohio, the European corn borer is the key pest that growers must battle every year [12]. The ECB is the primary insect pest of peppers in New Jersey, occurring every year throughout the state [13]. ECB overwinter as fully-grown larvae in plant refuse and debris, particularly in corn fields. Females may lay up to 500-600 eggs in clusters of 20- 30 eggs. Young larvae feed on the surface and within a day or two, tunnel into the fruit around the seed caps. The larvae feed in the core of the fruit or in the seed cavity. The larvae must be controlled before they enter the fruit. A near zero tolerance exists for peppers found with an ECB larva [12]. Recent tests with acephate show reductions of ECB infested peppers from 36% to zero [15]. Pepper yields were doubled in the acephate treatments resulting in an increased harvest of more than 40,000 peppers per acre [14].

Several species of lady beetles and the insidious flower bug feed on ECB eggs producing from 15 to 50% mortality. Stink bugs, damsel bugs spiders and hover fly larvae feed on young caterpillars. An imported parasitic wasp Macrocentrus grandii may kill up to 18% of the ECB larvae in Southern New England. Trichogramma releases resulted in an average of 9% of the sweet peppers damaged by European corn borers [26]. However, under high ECB pressure, 14-18% of the peppers were damaged in the trichogramma release plots [26]. Under moderate ECB pressure, Bt applied twice a week provided similar control (3% infestation) as permethrin applied weekly. Although expensive, Bt applications are highly preferable to extensive crop damage on organic farms.

Pepper Maggot

The pepper maggot is native to North America and it ranges from Massachusetts and Ontario west to Kansas and south to Florida and Texas. The pepper maggot has a patchy distribution throughout much of the eastern U.S. where the wild host is thought to be horse nettle. The pepper plant belongs to the nightshade family and is closely related to horse nettle. It was first reported as a pest of peppers in New Jersey in 1921 and has damaged up to 90% of unprotected pepper crops [16]. When the infested peppers were picked by the grower and shipped, they appeared to be normal, but when they arrived in nearby markets, particularly New York City, the peppers had become soft, watery and rotten. They settled considerably in the barrel and maggots were seen crawling out of the bottom [23]. The fly and maggot are often controlled by many of the insecticides that are commonly applied to pepper fields and tends to become problematic in the absence of routine cover sprays [16].

Pepper maggots overwinter in the pupal stage in the soil. Adult flies emerge in early spring and move to solanaceous host plants where they mate and lay eggs in the fruit.In the field males usually stay on one pepper plant for a considerable interval of time, 5 to 20 minutes, apparently waiting for a female. When a female appears, the male soon attempts to copulate. Copulation continues for 3 to 10 minutes. If a pair is disturbed when copulating, they may separate or the female flies away with the male attached [23]. Female flies insert single eggs under the skin of pepper fruit, which hatch in 8 to 14 days. The larvae feed on the spongy tissues inside of the fruit. Larvae remain in the peppers for about 2 to 3 weeks and emerge from the fruit to enter the soil. Only one generation occurs each season. One maggot can destroy an entire fruit. More importantly, peppers containing small larvae are often harvested with other peppers. Maggot infested peppers are not tolerated by the processor [17]. As the maggot matures inside the pod, the fruits turn red prematurely, becoming soft, watery and rotten. Soft spots can be seen where the maggot has fed on the pod walls. When infested fruit is picked, the cap usually separates from the pod because the maggot has eaten the core [17].

The pepper maggot fly uses the canopy of nearby trees as nonhost shelter sites when not mating or laying eggs in a pepper field. Research has been conducted with planting a perimeter of peppers around the main crop field of peppers which serves to act as a trap crop for the weevils when they fly to the pepper field. Insecticides are used to kill the weevil flies in the trap crop which then prevents movement into the main crop [16]. This technique can be used as part of an organic production system [16].

The use of insecticides is the only reliable method of pepper maggot control. In southern New Jersey, the recommendation is to apply an insecticide every ten days throughout July and early August.

Green Peach Aphid

The green peach aphid transmits a number of destructive viruses in pepper including pepper polyviruses and cucumber mosaic cucumovirus. These viruses frequently infect large numbers of plants and cause a considerable reduction in the yield of marketable peppers [37]. In addition it can damage the pepper plant by sucking plant sap. Extensive feeding causes plants to turn yellow and the leaves to curl downward and inward from the edges. Honeydew produced by the aphids can be a problem, especially on fresh market peppers [35]. Some natural parasitism of aphids occurs, but this is generally not sufficient for the needed levels of good control that insecticides provide [34].Lacewings, ladybugs, and some naturally occurring parasitic wasps provide moderate levels of control, but these biologicals generally do not provide commercially acceptable levels of control[34].Under favorable environmental conditions, populations of the green peach aphid can double in numbers within three days[37].In California, parathion was first mixed with DDT for aphid control. Insecticide tests demonstrated that sprays reduced the aphid population by 99% from 44 per leaf to less than one per leaf [36].

References

1. Riley, D. G. and A. N. Sparks, Jr., The Pepper Weevil and Its Management, Texas Agricultural Extension Service, Bulletin L-5069.

2. Sorensen, K. A. and C. C. Carter, Pepper Weevil, North Carolina State University, Agricultural Extension Service, Note No. 34, 1983.

3. Schuster, D. J., and P. H. Everett, “Control of the Beet Armyworm and Pepper Weevil on Pepper”, Proc. Fla. State. Hort. Soc., 95: 349-351, 1982.

4. Seal, D. R. and K. Bonardi, “Evaluation of Various Cultivars of Pepper for Resistance Against Pepper Weevil (Coleptera: Curculionidae)”, Proc. Fla. State. Hort. Soc., 112: 342-345, 1999.

5. Ozaki, H. Y. and W. G. Genung, “Insecticide Evaluation for Pepper Weevil Control”, Proc. Fla. State. Hort. Soc., 95: 347-348, 1982.

6. Elmore, J. C. and R. E. Campbell, “Control of the Pepper Weevil,” Journal of Economic Entomology, Vol. 47(6), December 1954.

7. Ingerson-Mahar, J., Pepper Weevil in New Jersey, New Jersey Agricultural Experiment Station, Cooperative Research and Extension.

8. Ryder, J. C., P. P. Burbutis, and L. P. Kelsey, “Systematic Insecticides for Control of European Corn Borer and Green Peach Aphid on Peppers,” Journal of Economic Entomology, Vol. 62(3), October 1969. 9. Hofmaster, R. N., D. F. Bray, L. P. Ditman, “Effectiveness of Insecticides Against the European Corn Borer and Green Peach Aphid on Peppers,” Journal of Economic Entomology, Vol. 53(4), August 1960. 10. Burbutis, P. P., R. VanDenburgh, D. F. Bray, and L. P. Ditman, “European Corn Borer Control in Peppers,” Journal of Economic Entomology, Vol. 53(4), August 1960.

11. Burbutis, P. P., et al., “European Corn Borer, Green Peach Aphid and Cabbage Looper Control on Peppers,” Journal of Economic Entomology, Vol. 55(3), June 1962.

12. Jasinski, J., et al., Bell Pepper and Non-Bell Pepper Pest Management Strategic Plan, Ohio State University Extension, 2003.

13. “Crop Profile for Peppers (Bell) in New Jersey,” May 2005, available at: http://www.ipmcenters.org/cropprofiles/docs/njpeppersbell.html

14. Kuhar, T. P. and J. Speese III, “Evaluation of Foliar Insecticides for Control of European Corn Borer in Peppers, 2001,” Arthropod Management Tests, 27, 2002. 15. Ladd, T. L., Jr., D. L. Reichard, H. R. Krueger, “Controlling Pests of Sweet Peppers with Reduced Amounts of Acephate and an Intermittent Sprayer,” Journal of Economic Entomology, Vol. 75(5), October 1982. 16. Boucher, T. J., et al., “Managing the Pepper Maggot (Diptera: Tephritidae) Using Perimeter Trap Cropping,” Journal of Economic Entomology, Vol. 96(2), April 2003.

17. Sorenson, K. A., “Pepper Maggot,” North Carolina State University, Vegetable Insect Pest Management, Insect Note #39, 1993.

18. Perry, R., Application for a Emergency Specific Exemption to Use Tebufenozide to Control Beet Armyworm on Peppers, Texas Department of Agriculture, 1998.

19. Guillebeau, P., N. Hinkle, and P. Roberts, Summary of Losses from Insect Damage and Cost of Control in Georgia, 2003, Miscellaneous Publication Number 106, March 2006.

20. Commercial Pepper Production Handbook, University of Georgia Cooperative Extension, Bulletin 1309, June 2006.

21. USDA/NASS, “Peppers, Bell: Pesticide, Total Acreage, Percent of Area Receiving Applications and Total Applied, Program State, and Total, 2000,” Agricultural Chemical Usage, July 2001.

22. Hofmaster, R.N., D.F. Bray, and L.P. Ditman, “Effectiveness of Insecticides Against the European Corn Borer and Green Peach Aphid on Peppers,” Journal of Economic Entomology, August 1960.

23. Peterson, A., The Pepper Maggot, a New Pest of Peppers and Eggplants, New Jersey Agricultural Experiment Stations, Bulletin 373, January 1923.

24. Brust, G., C. Mellinger, and G. Frantz, “A multi-tactic biologically-based approach to pepper weevil management in the eastern United States.”

25. Riley, D.G., D.J. Schuster, and C.S. Barfield, “Refined Action Threshold for Pepper Weevil Adults (Coleoptera: Curculionidae) in Bell Peppers,” Journal of Economic Entomology, 85 (5): 1919-1925, October 1992.

26. Kuhar, T.P., et al., “Potential of Trichogramma ostriniae (Hymenoptera: Trichogrammatidae) for Biological Control of European Corn Borer (Lepidoptera: Crambidae) in Solanaceous Crops,” Journal of Economic Entomology, 97 (4): 1209-1216, August 2004.

27. “Pepper Weevil,” Featured Creatures, University of Florida Institute of Food and Agricultural Sciences, Available at: http://creatures.ifas.ufl.edu/veg/beetle/pepper_weevil.htm. 28. “Peppers,” available at: http://www.web1.msue.edu/msue/imp/modae/visuals/581_17.jpg

29. “Bell Peppers: Estimated Production Costs in a Double-Crop System for the Palm Beach County Area, 2004-2005,” University of Florida.

30. “Table 53: Costs and Returns for Bell Pepper, Per Acre,” available at: http://aesop.rutgers.edu/~farmmgmt/ne-budgets/icm/bell-peppers.html

31. Cartwright, Bob, Tina G. Teague, Laurence D. Chandler, Jonahtan V. Edelson and G. Bentsen, “An Action Threshold for Management of the Pepper Weevil (Coleoptera: Curculionidae) on Bell Peppers,” Journal of Economic Entomology, Vol. 83, No. 5, October 1990.

32. Goff, C. C. and J. W. Wilson, The Pepper Weevil, University of Florida, Agricultural Experiment Station, Gainesville, FL, Bulletin 310, May 1937.

33. Campbell, Roy E. and J. C. Elmore, “Commercial Control of the Pepper Weeveil in California,” Journal of Economic Entomology, June 1942.

34. “A Pest Management Strategic Plan for Pepper Production in California,” The California Pepper Commission and The California Minor Crops Council, December 2004.

35. “Crop Profile for Bell Peppers in California,” available at: http://www.ipmcenters.org/cropprofiles/docs/CAbellpepper.html, Prepared: February 2000.

36. Elmore, John C. and Richard D. Magor, “Insecticide Experiments to Control Green Peach Aphid and Pepper Weevil on Peppers,” Journal of Economic Entomology, June 1962.

37. Shorey, H. H., “Effect of Various Insecticide Treatments on Populations of the Green Peach Aphid on Peppers in Southern California,” Journal of Economic Entomology, April, 1961.

38. Mayberry, Keith S., “Sample Cost to Establish and Produce Bell Peppers,” U.C. Cooperative Extension, Imperial County, 2000.

39. Takele, Etaferahu, “Bell Pepper Production: Sample Costs and Profitability Analysis,” Based on 1999 Data Collection in Ventura County, California, University of California: Agriculture and Natural Resources, Publication 8026.