Com rootworm

The com rootworms Diabrotica barberi and D. virgijera were controUed in the U.S. com belt from 1954 to 1964 by soil appHcations of heptachlor and aldrin. A resistant race of the western com rootworm D. virgijera was first characterized in southeastern Nebraska in 1961 and spread rapidly throughout the entire com belt. Successive introductions of carbamate and organophosphate soil insecticides have increased the cost of com rootworm control from... 

The Diabrotica spp. com rootworm beetles are specifically attracted to a variety of plant-produced phenylpropanoids, eg, ( )-cinnamaldehyde [14371-10-9] for the southern com rootworm D. undecimpunctata howardr, ( )-cinnamyl alcohol [4407-36-7] for the northern com rootworm D. barberi and indole [120-72-9] for the western com rootworm, D. virgifera virgifera. Especially powerflil lures for these rootworm beetles are 2-(4-methoxyphenyl)ethanol for the northern com rootworm and 4-methoxycinnamaldehyde [71277-11-7] (177) for the western com bootworm. 

Lin, S. and Mullin, C.A., Lipid, polyamide and flavonol phagostimulants for the adult Western com rootworm from sunflower pollen, J. Agric. Food Chem., 47, 1223, 1999. 

Jaspamide (17), previously mentioned in Section 17.3, is a modified peptide isolated from a Jaspis sponge. Jaspamide shows insecticidal activity against Heliothis virescens with an LCS0 of 4 ppm, as compared to 1 ppm for azadirachtin. Jaspamide (17), showed more than 72% mortality at 100 ppm to both southern com rootworm and tobacco budworm. Iso-domoic acids A (40), B, and C are novel amino acids from the red alga Chondria armata. They... 

The macrolide halichondramide (3)62 showed more than 75% mortality (100 ppm) against newly hatched larvae of the southern com rootworm, Diabrotica undecimpunctata howardi, and the tobacco budworm, Heliothis virescens.44 The dimeric macrolides swinholide A and... 

The homochiral f -branched carboxylic acids (13 or enf-13 Table 1) have been used for the synthesis of a variety of natural products21 such as California red scale pheromone,14 a-skytanthine,22 the southern com rootworm pheromone,15 and norpectinatone.16 Pure (5)-3-trichloromethylbutyric acid (a structural subunit of some sponge metabolites) was prepared via conjugate addition of ClaCMgCl to the chiral cro-tonate (16) followed by hydrolysis (Scheme S).23... 

Figure 16. Synthesis of the enantiomers of the southern com rootworm sex pheromone.

Aldrin from Corn. The most important use of aldrin is as a soil insecticide under corn. Here it is usually incorporated in the soil at application rates of 1-2 lb./acre to a depth of 3-4 inches. In muck soils the rate may be as high as 5 lb./acre. It is used to control the com rootworm and wireworm complexes plus other soil insects. 

Southern corn leaf blight, com and, 78 Southern com rootworms, 75,285, 285 Southernwood. See Artemisia abrotanum... 

CAS 1563-66-2. TM for a pesticide designed to combat com rootworm and rice water weevil. Approved by USDA. Also effective on alfalfa, sugarcane, rice, peanuts, and potatoes. 

The foregoing matters bring up the point that the com crop in the United States for the most part comprises a monoculture, and increasingly (or pervasively) consists of genetically modified subspecies. This may conceivably make the com crop more receptive to attack by the western com rootworm beetle, or still other unexpected pests. In other words, there is the need, or make it a necessity, for diverse species or subspecies rather than having a uniform monoculture. It is the old saw about not putting all of one s eggs in one basket. 

Prophos is a broad-spectrum nematocide and insecticide, and is used mainly for resistant and nonresistant com rootworm control. It is used as a liquid spray or as formulations containing solid vehicles or extenders. Its half-life in the soil varies between 3 and 12 days depending on the application rate, formulation, type of soil and other factors. 

Figure 4.22. Natural products synthesized by asymmetric 1,4-addition of cuprates to esters citronellic acid [124] California red scale pheromone [129] mycolipenic acid (W. Oppolzer T. Godel, unpublished, quoted in [130]) the alleged norpectinatone [128] vitamin E side chain (W. Oppolzer R. Moretti, unpublished, quoted in [ 130]) southern com rootworm pheromone...

Cucurbitacin B evokes chemosensory responses at levels as low as 0.1 uM, probably acting at a different modulatory site than do classical synaptic y-aminobutyric acid (GABA) and glycine receptor-channel complexes. Chyb et al. [83] studied adult western com rootworm (Diabrotica virgifera virgifera, Coleoptera-Chrysomelidae) beetles and reported the possibility that there are peripheral chemosensory receptor sites that may resemble, both functionally and structurally, synaptic receptor sites in the CNS. 

Some studies hypothesize about the protection of cucurbitacins against soil borne fungal entomopathogens, both in the adult com rootworm and in the eggs laid in the soil. However, Martin et al. [84] demonstrated that cucurbitacins do not inhibit fungal growth, as seen by the fact that the sterilized extract containing them showed no activity. These authors thus hypothesize that the activity may actually be due to bacteria associated with the plants. 

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