Corn rootworm

Meinke, LJ USDA To study the influence of methyl parathion on western corn rootworm behavior and population dynamics. 

Meinke, LJ USDA Western corn rootworm resistance to methyl parathion-development of resistance management strategies... 

Wright, RJ USDA To document the extent of adult corn rootworm beetles resistence to methyl parathion throughout Nebraska. 

The compounds that we will consider here, in contrast, serve quite specific needs of various organisms, and for this reason we will call them special chemical compounds. Different species may employ the same special compound, in some cases for the same purpose and in other cases for different ends. For example, the carbon dioxide arising from the respiration of a crowd of ants is an aggregation signal that invites solitary ants to join their nestmates. Corn rootworms, however, use the carbon dioxide that living corn roots emit into the soil as a signal, leading them to their food. Different species may also employ diverse compounds for essentially the same purpose. Various ant species mark their food trails with different chemicals to keep their food sources secret from one another. 

Harris CK, Chapman RA, Tolman JH, et al. 1988. A comparison of the persistence in a clay loam of single and repeated annual applications of seven granular insecticides used for corn rootworm control. J Environ Sci Health [B] 23 1-32. 

Symptoms Southern corn rootworms feed on corn roots, often killing young plants and weakening older ones. Striped cucumber beetle larvae feed on the roots of squash-family plants only, killing or stunting the plants. Adults of both species feed on leaves, stems, flowers, and fruit of squashes and other crops. 

Because of their similar life cycles, habits, damage to corn, and apparent resistance to conventional corn rootworm insecticides, we could expect both the PSB and HBV to increase their densities and/or range throughout the Midwest much as the PSB has (9,12). These concerns are evident in the 1985 establishment of a multistate regional research effort entitled "Impact of integrated crop management practices on European corn borer and related stalk boring insects". 

Insecticides Vetch aphid (Megoura viciae) bollworm (Helicoverpa zea) army worm (Spodoptera littoralis) diamondback moth (Plutella xylostella) mustard beetle (Phaedon cochleariae) corn rootworm (Diabrotica undecimpunctata) whitefly Bemisia tabaci) red spider mite (Tetranychus urticae). 

B (4, 5),63 64 showed more than 93% mortality (100 ppm) against newly hatched larvae of corn rootworm and tobacco budworm. 

We mentioned earlier the in vitro antimalarial activity of halichondramide and swin-holide A.22 The initial testing of compounds 3 to 5 displayed 75 to 100% mortality of both corn rootworm and tobacco budworm. On titration, they displayed an LCS0 range of 10 to 100 ppm, and induced 30, 85, and 30% corn rootworm larval stunting, respectively. Both halichondramide and swinholide A caused 85% tobacco budworm larval stunting. The significant insecticidal activity of these compounds (3 to 5) indicates that further QSAR studies of the compounds would be valuable. These compounds illustrate the necessity to examine various marine macrolides as potential prototype insecticides. 

The peak period for the use of aldrin and dieldrin was between the late 1960s and the early 1970s throughout various parts of the world (WHO, 1989). The use pattern of aldrin and dieldrin are quite similar. They act as effective contact and stomach poisons for insects. They are used to control soil insects (e.g. grasshoppers and corn rootworm), and protect crops and wooden structures from termites (WHO, 1989). The production of aldrin and dieldrin has decreased since the early 1960s. In the United States, the peak use of aldrin from 19 million pounds in 1966 decreased to 10.5 million pounds in 1970 (USEPA, 1980). During this same period (1966-1970), annual dieldrin use dropped from 1 million to 670,000 pounds. These decreases were primarily due to increased insect resistance to the aldrin and dieldrin, and to the development and availability of more effective and environmentally friendly pesticides (USEPA, 1980). 

The entire subject has been reviewed in detail several times.32,56,57,65 Recently, a new adsorptive method for the isolation of DIMBOA has been reported.49 The impact of benzoxazinoids on the western corn rootworm (Diabrotica virgifera LeConte) development has been studied.17 The allocation of a hydroxamic acid and biomass during vegetative development of rye has been investigated.27 Effects of benzoxazinoids from maize on survival and fecundity of aphids have been explored.13 DIMBOA concentrations have been measured in various isolines of wheat and corresponding plant introduction lines.55 The variation of the content of several benzoxazinoids in relation to the age and plant organ has been determined in maize plants.12... 

Davis, C. S., Ni, X. Z., Quisenberry, S. S. and Foster, J. E. 2000. Identification and quantification of hydroxamic acids in maize seedling root tissue and impact on western corn rootworm (Coleoptera Chrysomelidae) larval development. J. Econ. Entomol. 93, 989-992... 

Other plant-feeding insects, such as the cabbage looper, have piled one resistance upon another, so that we must look to pheromones and chemosterilants for their control. The western corn rootworm has now joined the onion maggot in going OP-resistant. Resistance problems on pests of rice in Japan are becoming as severe as those on cotton in the Americas. 

It should be clear to us that the development of resistance is always to be expected to any insecticide we may choose to apply, but it is not inevitable. DDT stayed effective against the European corn borer for at least 15 years (Table VIII) and there are several other examples, including diazinon and the western corn rootworm in Nebraska. Some of the species of beneficial insects which formerly suffered from insecticide damage, such as braconid parasites, lady beetles, mayfly nymphs and honeybees, have now developed certain tolerances, while several of the Phytoseiid mites which feed on the plant-feeding spider mites are becoming as resistant as their prey to OP s and carbamates. 

W. Spruce Budworm W. Corn Rootworm mexacarbate diazinon Idaho Neb. 1963-73 14 gen 5... 

Southern corn rootworm. The structure of the southern corn rootworm has been defined as 10-methyl 2-tridecanone, XI (Figure 16) (5J3). Alkylation of undecanoic acid with n-propyl bromide was followed by conversion to the diastereomeric amides with either (S)- or (R)-a-methylbenzylamine that had been purified previously by recrystallization of D and L tartaric acid salts, respectively. Recrystallizations of these amides from ethanol (4 was sufficient) gave 32% yields of pure (>99.5%) diastereo-mers (Figure 16). Hydroxyethylation labilized the amides toward hydrolysis. It was convenient to intercept the aminoesters and reduce them with LAH. The resulting carbinols were than carried forward in standard manner to provide the ketones. 

Figure 15. Synthesis of the enantiomers of the western corn rootworm sex pheromone.

The blossoms of Cucurbitaceae are well known to be highly attractive to many species of Diabrotica beetles. However, the volatile compounds that act as attractants differ in different Diabrotica species. Cinnamaldehyde strongly attracts the spotted cucumber beetle, Diabrotica undecimpunctata hoivardi, whereas 4-methoxycinnamaldehyde is a specific attractant for the western corn rootworm, Diabrotica virgifera virgifera.51 The northern corn rootworm, Diabrotica barberi, and Diabrotica cristata are attracted to eugenol, cinnamyl alcohol, and 2-(4-methoxyphenyl)ethanol. Volatiles of maize, one of the host plants, also attract D. v. virgifera... 

In this very large coleopterous family the sex pheromone of only two species have been identified. Dlabrotlca vlrglfera vlrgjfera LeConte, the western corn rootworm (VCR), produces and responds to... 

WCR = western corn rootworm, MCR = Mexican corn rootworm, NCR = northern corn rootworm. 

The pheromone of the southern corn rootworm (SCR), D. undedmpunctata howardii Barber, was identified as (R)-10-methyl-2-tridecanone (40). Since it has only one asymmetric carbon, it can exist in only two enantiomeric forms. Synthesis of both the (R)- and (S)-enantiomers by Sonnet (41) in high enantiomeric purity again provided material for field tests. SCR males respond only to the (R)-enantiomer in the field. 

Trimethacarb is a stomach poison insecticide with some contact activity used for controlling corn rootworm larvae and other insects, and mollusk pests. Its oral LD30 in rats is 125 mg/kg. 

Figure 10.6 Relationship between generations per year and development of resistance in species selected by soil application of aldrin/dieldrin. 1 and II, root maggots III, southern potato wireworm IV, northern corn rootworm V, European chafer VI, Japanese beetle VII, sugarcane wireworm. (From Georghiou, G.P. and Taylor, C.E., in Pesticide Resistance Strategies ami Tactics for Management, National Academy Press, Washington, D.C., 1986,157 With permission.)...

Hollister B, MuUin CA (1999) Isolation and identification of primary metabolite feeding stimulants for adult western corn rootworm, Diabrotica virgifera virgifera Leconte, from host pollens. J Chem Ecol 25 1263-1280... 

---