Western 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... 

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. 

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. 

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... 

This is a review of synthetic efforts made at these laboratories in recent years. Stereoisomers of sex pheromones of various insect species were synthesized in order to facilitate identification and permit more thorough evaluation of their potential in insect control programs. Syntheses are described for pheromones of the stable fly, tsetse fly, southern and western corn rootworms, and the Mediterranean fruit fly attractant, trimed-lure. In each instance centers of asymmetry were generated that made use of diastereomer formation using readily available (R)- and (S)-a-methyl-benzylamine. Resolutions were achieved either by preparative HPLC, or fractional crystallization of amides. The latter technique was rendered synthetically useful for the preparation of configurationally pure acids by virtue of transformations wrought upon the amides that made them subject to cleavage under very mild conditions. 

Another important member of this family is the western corn rootworm, Diabrotica virgifera virgifera LeConte. Our research with this insect s sex pheromone gave ample indication that much can be learned both by biologists and chemists if a project to identify chemical cues is not focused solely on a designated pest species, but is instead broadened to encompass closely related species. 

The structure of the western corn rootworm sex pheromone is 8-methyl-2-decanol propanoate (] 6) and four stereoisomers are possible (Figure 7). In our synthesis (3), we coupled a chiral 5-carbon unit to a 6-carbon fragment that had the requisite substitution to allow resolution at the oxygenated carbon. As mentioned earlier, (S)-2-methylbutyric acid was available to us from the alcohol. D-Isoleucine served as a source for the (R)-acid. Nitrosation, followed by decarboxylative oxidation of the intermediate hydroxyacid led to the (R)-2-methylbutyric acid in 96% ee. The process of fractional crystallization was... 

The toxicity by ingestion and effects on growth and reproduction were evaluated by incorporation of the chemicals into the ground cat chow diet of the German cockroaches (9). Lavicidal and ovicidal activity against the western corn rootworm Diabrotica vergifera verglfera) were tested in petri dishes of soil and on moist blotter paper, respectively (4). 

Examples of the use of these chiral building blocks in the synthesis of drugs and natural products abound in the literature. They include the synthesis of grahamimycin the macrocyclic component of the antibiotic elaiophylin, fungicides norpyrenophorin, pyrenophorin and vermiculin, phorcantholide I and J, which are defensive secretions of the eucarypt longicorn beetle,citronellol and a pheromone of the western corn rootworm. Clearly the monomeric chiral derivatives of PHB have a role to play in enantiomer-specific synthesis. 

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