Field crops insect pests

A recent thorough review of attempts to control the cotton boll weevil by means of pesticides (592) makes it unnecessary to go into detail here, but some perspective is presented, since the problem is massive and attempts to control this insect with pesticides have contributed to the difficulties alluded to in Section VII. A. One third of the agricultural pesticides used in the U. S. is dedicated to attempted control of the cotton boll weevil (592). 

Lloyd (595) found that the theoretical study of Knipling was validated by our [Mitchell et al, above] field research. The debate on 

With the exception of the corn earworm, fall armyworm, pink bollworm, and Egyptian cotton leafworm programs, these disruption tests were preliminary studies carried out on small plots without optimization of disruptant formulations and with little assessment of crop damage. 

Mitchell (597) has discussed the feasibility of using multicomponent formulations for control of several important pests of field crops. Hendricks et al. (600) showed that a mixture of looplure (622) and virelure (623, 624) were compatible and caught the cabbage looper (T. ni), the soybean looper (Pseudoplusia includens), and the tobacco budworm (H. virescens) on the same traps. It seems likely that pesticide applications to field crops could be greatly reduced by means of pheromone-baited monitoring traps, and such efforts will undoubtedly become a part of the integrated pest management projects now established by the Extension Service of the USDA. 

Another cotton pest in several parts of the world is the red boll-worm, Diparopsis castanea. Its pheromone and an inhibitor have been shown to disrupt mating, but no crop damage assessment was made (607). 

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Pyrethroids are a class of synthetic chemicals that are similar in structure to natural pyrethrins. They have been used in field crops and urban pest management for nearly 30 years, and within the last 5 to 10 years new products have been registered for specific use against stored-product insects. Resmethrin is labeled for use as an aerosol in food plants, mills, and warehouse facilities, but could have potential side effects such as discoloration of surfaces and odor contamination and may be more appropriate for use in empty facilities. Labels generally state to cover any food prior to application. The pyrethroids esfenvalerate (Conquer) and prallethrin (Etoc) are also labeled for use in some situations as an aerosol space treatment in... 

It is very fortunate for the rice producers of the United States that rice, as compared to most crops, is relatively free from insect pests. Metcalf and Flint (2b) list 30 species of insects as being injurious to corn, 20 to wheat, rye, and barley, 31 to leguminous crops, and 23 to cotton, as compared to but 4 for rice. The fact that rice fields are flooded a large portion of the growing season results in ecological conditions unfavorable to numerous insects that otherwise would probably attack this crop. 

Rice Water Weevil (Lissorhoptrus simplex). Isely and Schwardt (16) who worked with this insect from 1930 to 1933, inclusive, state, The rice water weevil is the most important insect pest of rice in Arkansas. It seems likely that this statement also applies to most of the other rice-producing areas of the southern states. Although the adult weevils feed to a considerable extent on rice leaves, the principal injury is caused by the larvae feeding on the rice roots. Under conditions of heavy infestations practically all the roots are destroyed approximately 4 to 5 weeks from the time of the first flooding of the fields. Normally, even under such conditions, the rice is not killed and when the larvae have matured and ceased feeding, the plants produce a new set of roots and will still produce a crop. The severe setback given the plants during this period naturally results in a marked reduction in yield. 

Contamination of crops and products with ochratoxin A and related metabolites is not as directly associated with a particular fungus as is the case with the aflatoxins. Ochratoxin A is also likely to occur with other mycotoxins, such as citrinin and penicillic acid or patulin. In addition, it is not certain whether ochratoxin A contamination is only a storage problem or perhaps a dual field and storage problem. In cases such as coffee crops, the use of insecticides might help to control insect activity and consequently fungal infection. Coffee-berry borers are a major insect pest which can act as vectors to carry fungal spores, resulting in crop infection and ochratoxin accumulation. 

Diazinon is the common name of an organophosphorus insecticide used to control pest insects in soil, on ornamental plants, and on fruit and vegetable field crops. It is also used to control household pests such as flies, fleas, and cockroaches. This chemical is synthetic and does not occur naturally in the environment. Diazinon is sold under common trade names including Alfatox, Basudin, AG 500, Dazzel, Gardentox, and Knoxout. 

Pyrethroids are synthetic esters produced to imitate or improve the activity of biological principles of the pyrethrum plant. They are powerful contact insecticides causing rapid knockdown of treated insects. The pyrethroids are extensively used in controlling insect pests on fruit trees, vegetables, and other field crops in space sprays and contact sprays to kill insects infesting homes, industrial locations, and nonfood processing areas and in protection of warehoused food. These compounds include fenvelerate [51630-58-1], (7), R = Cl flucythrinate [70124-77-5], (1) R = CHF20 allethrin [584-79-2] (8) cyfluthrin [68359-37-5] (9) cypermethrin [52315-07-8] (10) deltamethrin [52918-63-5] (11) permethrin [52645-53-1] (12) and tetramethrin [7696-12-0] (13). 

For the 2000 growing season, the National Agricultural Statistics Service (NASS) of the USDA surveyed adoption of individual IPM practices (USDA-NASS, 2001). A summary of results for the major field crops, fruits and nuts, and vegetables is presented in Table 32.5. The adoption of systematic scouting for pests (weeds, insects, or plant diseases) looks very promising. 

Uses insecticide to control mosquito larvae, house flies, and other insect pests in field crops, fmits, and vegetables ... 

Uses Trichlorfon is a pale, clear, white, or yellow crystalline solid with an ethyl ether odor. It is a solid at room temperature. Trichlorfon is grouped by the USEPA under GUP. Trichlorfon is used for the control of a variety of insect pests, (e.g., cockroaches, crickets, silverfish, bedbugs, fleas, cattle grubs, flies, ticks, leafminers, leafhoppers). It has extensive use in agriculture, applied to vegetable, fruit, and field crops. 

Cultivation, moldboard plowing, and burning of crop residues soon after harvest greatly aid in the control of some insect pests on agricultural crops. Pink bollworm infestations in cotton, for example, can be greatly reduced by plowing the field immediately after harvest. 

The insect problem is insidious, Grain may become infested in (he field and the pest carried into a clean store (Giles and Ashman, 1971). Small amounts of infested grain from the previous year s crop, lodged in crevices, can effect a rapid infestation of the new crop. Insects thrive on a wide range of conditions (Howe, 1965) and constitute a threat in most parts of the world. 

The lepidopteran genus Heliothis includes some species that are among the most important of all phytophagous insect pests. The Heliothis complex has worldwide distribution and is responsible for economic losses over a wide range of field and horticultural crops. In the USA, two species of these pests -- Heliothis zea (Boddie) otherwise known by the common names bollworm, com earworm, tomato fruitworm, etc. and the tobacco budworm, Heliothis virescens (F.)... 

Wraight SP, Carruthers RI. Production, delivery and use of mycoinsecticides for control of insect pests on field crops. In Hall FR, Menn JJ, eds. Methods in Biotechnology 5, Biopesticides Use and Delivery. Totowa, NJ Humana Press, 1999, pp 233-269. 

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