Fall armyworm

Wadleigh RW, Yu SJ (1987) Glutathione transferase activity of fall armyworm larvae toward alpha-, beta-unsaturated carbonyl allelochemicals and its induction by allelochemicals. Insect Biochem 17 759-764... 

Yu SJ (1982) Host plant induction of glutathione S-transferases in the fall armyworm. Pestic Biochem Physiol 19 101-106... 

Yu SJ (1983) Induction of detoxifying enzymes by allelochemicals and host plants in the fall armyworm. Pestic Biochem Physiol 19 330-336 Yu SJ (1984) Interactions of allelochemicals with detoxification enzymes of insecticide-susceptible and resistant fall armyworms. Pestic Biochem Physiol 22 60-68 Yu SJ (1986) Consequences of induced foreign compound-metabolizing enzymes in insects. In Brattsten LB, Ahmad S (eds) Molecular aspects of insect-plant associations. Plenum, New York, pp 153-174... 

Cuts from the silica gel column were incorporated into artificial diets optimized for several economically-important agricultural pest insects, the pink bollworm Pectinophora gossypiella> the tobacco budworm Heliothis virescens> the corn earworm H. zea and the fall armyworm Spodoptera frugiperda. > Monitoring with this artificial diet bioassay, further column chromatography and preparative TLC on silica gel in diethylether-petrol yielded five... 

Our initial studies (25,26) determined the comparative fate of a radiocarbon-labeled preparation of the commonly occurring linear furanocoumarln, xanthotoxln (8-methoxypsoralen) in black swallowtail caterpillars and in fall armyworm (Spodoptera frugiperda J. E. Smith) larvae. Black swallowtail caterpillars are known not to be adversely affected by linear furanocoumarlns (22), while Spodoptera spp. avoid such plants as food sources... 

Figure 2. Major metabolites of xanthotoxin (8-methoxypsoralen) in last-stage larvae of the black swallowtail butterfly (Papilio polyxenes) and the fall armyworm (Spodoptera frugiperda).

Southern and fall armyworm growth on pulegone-laced diets... 

Figure 2. Growth from fourth instar to pupation on control or pulegone-containing diet of fall armyworm larvae (11) (top) and southern armyworm larvae (13) (bottom). Key , control A, O.OI % pulegone and A. 0.1 % pulegone.

Figure 3. Electron micrograph of a fall armyworm, Spcxloptera frugiperda, after ingestion of the crude methanol extract of Ajuga remota roots. This insect has three head capsules that mask its functional mouthparts. The insect eventually starved to death. Magnification X.38.

Figs. 3 and 4 are electron micrographs of a fall armyworm, and a pink bollworm, respectively. Both Insects have three head capsules because they underwent two failed molting cycles before death. That Is, even though feeding became Impossible after the first Inhibited ecdysls because the adhering second head capsule covered the mouthparts, these larvae could synthesize a third head capsule. ... 

Yu S. J. (1983) Induction of detoxifying enzymes by allelochemicals and host plants in the fall armyworm. Pest. Biochem. Physiol. 19, 330-336. 

Sf-9 cells are derived from the IPLBSF-21 cell line, isolated by Vaughn et al. (1977) from pupal ovarian tissue of the fall armyworm Spodoptera frugiperda. This cell line is commonly used for bioproduct expression employing baculovirus as vectors, similarly to the High-Five cell line. 

BARTELT, R.J., MIKOLAJCZAK, K.L., Toxicity of compounds derived from Limnanthes alba seed to fall armyworm (Lepidoptera Noctuidae) and European com borer (Lepidoptera Pyralidae) larvae., J. Econ. Entomol., 1989,82, 1054-1060. 

Table 5.2 Toxicity of insecticides applied topically to various instars of fall armyworm larvae...

The quantity and quality of food in the diet on which insects are reared may affect their size and survival capacity. Variegated cutworm larvae fed peppermint leaves were more tolerant of the insecticides carbaryl, acephate, methomyl, and malathion than larvae fed snap bean leaves. Increased tolerance for carbaryl and methomyl was also observed in larvae of the alfalfa looper and cabbage looper when they were fed peppermint plants instead of their favored host plants alfalfa and broccoli. Furthermore, fall armyworm larvae fed corn leaves became less susceptible to the insecticides methomyl, acephate, methamido-phos, diazinon, trichlorfon, monocrotophos, permethrin, and cypermethrin than those fed soybean leaves. Although nutrition may play some role in these cases, it was found that enhanced insecticide tolerance caused by these host plants was mainly due to plant allelochemicals, which induced detoxification enzymes in the insects (Yu, 1986). 

Yu, S. J., Age variation in insecticide susceptibility and detoxification capacity of fall armyworm (Lepidoptera Noctuidae) larvae, /. Econ. Entomoi, 76, 219,1983. 

Carboxylesterases are responsible for the selective toxicity of malathion that favors mammals over insects. Carboxylesterase hydrolyzing trans-permethrin has been found in numerous insect species, including the fall armyworm, velvetbean caterpillar (Anticar-sia gemmatalis), cabbage looper (Trichoplnsia ni), tobacco budworm (Heliothis virescens), corn earworm (Helicoverpa zea), and spined soldier bug (Podisus maculwentris) (Yu, 1990). 

Insecticide Spined soldier bug Velvetbean caterpillar Fall armyworm Corn earworm... 

Table 9.16 Glutathione S-transferase activity of fall armyworm larvae fed various host plants...

Further studies reveal that corn leaves, a potent inducer of microsomal monooxygenases, cause fall armyworm larvae to become less susceptible to the insecticides methomyl, acephate, methamidophos, diazinon, trichlorfon, monocrotophos, permethrin, and cypermethrin than soybean-fed larvae. 

Induction of glutathione S-transferases by phenobarbital in houseflies provides some protection against the toxicity of methyl parathion, methyl paraoxon, azinphosmethyl, and methidathion. Similarly, induction of glutathione S-transferase by host plants in fall armyworm larvae protects the larvae against organophosphate insecticides. Larvae fed... 

As mentioned earlier, atrazine induces various detoxification enzymes in insects. Table 9.18 shows that the induction by atrazine was associated with decreased toxicity of carbaryl, permethrin, and indoxacarb but increased toxicity of methyl parathion, phorate, and trichlorfon in fall armyworm larvae. The increased toxicity of methyl parathion and phorate was likely due to enhanced microsomal desulfuration and sulfoxidation, respectively, by atrazine (see the following text for explanation). 

McCord, E., Jr. and Yu, S.J., Mechanisms of carbaryl resistance in the fall armyworm, Spodoptera frugiperda (J. E. Smith), Pestic. Biochem. Physiol., 27,114,1987. 

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