Rootworm control

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... 

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. 

The perspective that "The persistent chlorinated hydrocarbons appear to be uniquely well adapted for soil use" (3) rather quickly collided with the reality of insect microevolution. The first evidence of rootworm control failures occurred in Nebraska in 1959, and by 1962 resistance of rootworms to the cyclodienes had been conclusively documented (4). The spread of this resistance during the 1960 s, along with environmental scrutiny of the ecological impacts of these persistent compounds, created a demand for more environmentally sound insecticides. 

Beginning in the mid to late 1960 s the biodegradable organophosphorus and carbamate insecticides began to replace the chlorinated hydrocarbons as the rootworm control chemicals of choice. Dlazinon, oxydisulfoton, and phorate were the first, and were quickly followed by bufencarb, trimethacarb, fonofos, and fensulfothion. In the mid to late 1970 s the introduction of new chemicals continued as ethoprop, carbofuran, chlorpyrifos and terbufos came into use. 

Field Evaluation of Chemical Rotations. During 1985-1988, experiments were conducted at the Univ. of 111. Northwest Illinois Agricultural Research and Development Center near Monmouth, Illinois. A single 2-acre field was used over the 4 years of research. The soil was a Muscatine silt loam and the slope was 2% (soil 69, Table I). The cropping history prior to 1985 was soybeans, 1980-82 wheat, 1983 corn, 1984. No soil insecticide had been used for at least three years prior to 1985. Chlorpyrifos (Lorsban 4E) was used for adult corn rootworm control during 1984. 

Table II. Rootworm Control in Carbofuran and Ethoprop History Soils...

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. 

The four-day acute greenhouse evaluation of these materials (Table I) indicated that comparable rootworm control was produced with (1), (2), and the TAG lot (test... 

EL-499 is a potent uncoupler of oxidative phosphorylation in vitro and exhibits hydrolytic lability under conditions involving either heating with base in solution or incubation in soil. The small differences observed in acute toxicity with isomers (1) and (2) and a wide variety of alpha-branched perfluorinated alkyl substituents reported earlier (8) further indicates that there exists only a generalized lipophilic structural requirement for activity/ ie. alpha-branching. Indeed, if there is an uncoupler binding site, (17/18) it is expected that molecular recognition is associated principally with the aniline ring and its substituents. Under more severe hydrolytic conditions, differentiation of even the alpha-branched perfluorinated carboxanilides is observed, which manifests itself in differential residual corn rootworm control. 

Al-Deeb, M.A., G.E. Wilde, J.M. Blair, and T.C. Todd. 2003. Effect of Bt corn for corn rootworm control on non-target soil microarthropods and nematodes. Environ. Entomol. 32 859-865. 

Higgins, L. and D. Wright. 2003. Evaluation of the Impact of Corn Rootworm Control Strategies on Non-Target Arthropods. Project Number PHI/2001/020. Unpublished study prepared by Pioneer Hi-Bred International, Inc. 85 p. 

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