Tobacco budworm, Heliothis virescens

The continuing use of pyrethroids in agriculture has led to the emergence of resistant strains of pests. One of the best-studied examples is the tobacco budworm (Heliothis virescens), a very serious pest of cotton in the southern United States (McCaffery... 

Several species of lepidopterous larvae cause bollworm-type injury to bolls and squares throughout the tropics. They include the bollworm [Heliothis armigera (Hbn.)], the tobacco budworm [Heliothis virescens (F.)], the black bollworm (Pro-denia latisfascia Wlk.), and in Peru Mescinia peruella Schaus. 

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... 

Cuticular diterpenes-duvanes and labdanes. Cutler have found that the cuticular diterpenes of green tobacco have both allelopathic and insect-deterrent effects (38). Present in the cuticle are duvane and/or labdane diterpenes (Figure 3) The levels of these specific cuticular components are believed to be responsible for the observed resistance of some types of tobacco to green peach aphids Myzus persicae (Sulzer), tobacco budworm Heliothis virescens (F.), and tobacco hornworm Manduca sexta (L.) (39). 

Hedin, P.A. et al.. Multiple factors in cotton contributing to resistance to the tobacco budworm Heliothis virescens F., in Plant Resistance to Insects, Heden, P.A., Ed., American Chemical Society, Washington, 1983, 347. 

The effects of selected fatty acid (Cio-Cia) methyl esters on the pink bollworm (Pectinophora qossypiella). bollworm (Heliothis zea) and tobacco budworm (Heliothis virescens) were determined, and a number of cyclopropyl, olefinic and acetylenic methyl esters were also tested (115). Methyl (Z,Z)-deca-2,8-diene-4,6-diynoate (matricaria ester) was lethal at low concentrations to all three insects. This last ester was isolated from Conyza canadensis but is found in vegetative matter of many plants of the Asteraceae. 

Multiple Factors in Cotton Contributing to Resistance to the Tobacco Budworm, Heliothis virescens F. 

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... 

Z)-9-tetradecenal (with (Z)-11-hexadecenal) [53939-27-8] CH3CH2CH2CH2CH=CH(CH2)7CHO tobacco budworm, Heliothis virescens... 

The sex attractant of the eastern spruce budworm, Choristoneura fumiferana, is (E)-ll-tetradecenal (73). A probable precursor, (E)-ll-tetradecen-l-ol, is produced in the sex attractant gland (74), but this compound, which inhibits the male response to the aldehyde, does not appear to be released by the calling female. The (Z)-isomer of tetradecenal has been identified as one of the sex pheromones of the tobacco budworm, Heliothis virescens it is accompanied by (Z)-ll-hexadecenal (75, 76)7 Similarly, the female of the striped rice borer secretes two alkenals--(Z)-ll-hexadecenal and (Z)-13-octadecenal as its sex pheromone blend (77). 

A number of insect species, including corn earworm, Heliothis zea (Boddie), and tobacco budworm, Heliothis virescens (F.), contain and C,g aldehydes (C al and C al) in their pheromone blends (22, 23). The release rate of a C. al would be expected to be higher than that of a Cj al because of the molecular weight difference. A mixture containing 10% n-tetradecanal (CjA°al) in Z)-ll-hexadecenal [(J0-Il-Cj al] was formulated in four laminates, each made from a different type of polymeric membrane as the top and bottom layers vinyl, Mylar -coated vinyl, acrylic, and rigid vinyl film. (The saturated C,.°ol was used as a model because of availability.) The total alaehyde content was approximately 2.3 mg per cnr of laminate 0.7% (of the pheromone weight) of 2,6-di-tert-butyl-4-methylphenol (BHT) was added as an antioxidant. Table II gives the thickness of the polymers. 

Much interest has been shown in the biosynthesis of insect juvenile hormones (62 R1, R2 = Me or Et). In adult male moths, [l-14C]propionate was specifically incorporated into juvenile hormone I [JH-1, (62 R1 = R2 = Et)], and tracer was only found at, and equally distributed between, C-7 and C-ll.90 Application of [2-14C]-and [3-14C]-propionate led to extensive randomization of label, which suggests that C-2 and C-3 formed in propionate catabolism can be re-used as smaller fragments, whilst C-l is either removed from propionate in a metabolically active form or is highly diluted. Ternary complexes of brain, corpora cardiaca, and corpora allata from the tobacco budworm Heliothis virescens produced labelled JH-I and JH-II (62 R1 = Et, R2 = Me) when incubated with L-[Me-14C]methionine or sodium [l-l4C]propionate.91 Partial degradation of the juvenile hormones showed that in JH-I portions a and /3 (62) had incorporated one atom of tracer from each propionate, whereas fraction y was unlabelled, and in JH-II only fraction a was... 

Recent publications 0,4) in regard to the latter two plants indicate that they were also toxic to two bacteria which occur in the gut of the tobacco budworm Heliothis virescens (Fab.) and the corn earworm Heliothis zea (Boddie). The compounds, rhamnetin 3-0-glucoside and isoquercitrin, were isolated (3) from H camporum based upon their activity against Pseudomonas maltophilia and Enterobacter cloacae Also, a procyanidin was isolated (4) from Mj floribundum on the basis of activity against P. maltophilia. 

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). 

Recent studies have confirmed that the phytoalexin isolated from species of cotton (Go55ypmw) infected with the fungus Verticillium dahliae is hemigossypol (161) (cf. Vol. 6, p. 66) and not, as previously reported,isohemigossypol (162). A related compound, p-hemigossypolone (163) has been identified as one of the compounds which inhibits the growth of tobacco budworm (Heliothis virescens)in cotton buds. ... 

A case in point is the unraveling of resistance to methyl parathion in the tobacco budworm, Heliothis virescens, which is a major pest of cotton as well as tobacco. In South Carolina, there is very severe, stable resistance. Although pyrethroid insecticides are very effective and there is no resistance to them in South Carolina at this time, it would be very useful to understand the genetic basis of methyl parathion resistance in case resistance to pyrethroids should arise in the future or spread eastward from Texas where it has been detected. Recent investigations with this pest will be described to illustrate certain mechanisms. 

The lepidopteran genus Heliothis includes some species that are among the most important of all phytophagous insect pests. The Heliothis complex has worldwide distribution and is responsible for economic losses over a wide range of field and horticultural crops. In the USA, two species of these pests -- Heliothis zea (Boddie) otherwise known by the common names bollworm, com earworm, tomato fruitworm, etc. and the tobacco budworm, Heliothis virescens (F.)... 

These compounds were tested against a series of Lepidoptera imder standard laboratory procedures. Activity on diamondback moth (PluteUa xylostdla, Px), fall armyworm (Spodoptera frugiperda, Sf), and tobacco budworm (Heliothis virescens, Hv) was evaluated. Insecticidal potency is reported as the LCjq in ppm. Comparison of the insecticidal activity for compounds D1-D3 identifies several key structural features of importance (Table 1). Our initial lead compoimd D1 was effective on the species S/and Px with LCjq values of 68.9 and 16.8, respectively, but with no activity on Hv. Incorporation of a 2-methyl group on the benzamide,... 

Southern armyworm (Spodoptera eridania) Tobacco budworm (Heliothis virescens) Two-spotted spider mite (Tetranychus urticae) Western potato leaf hopper (Empoasca abrupta)... 

In contrast to the mammalian and avian studies, the available information on the metabolism of the spinosyns by insects suggests that metabolism of the spinosyns (e.g., spinosyn A) is very limited. Studies of spinosyn A metabolism in tobacco budworm Heliothis virescens) larvae show that the only component detected (within the limits of detection, up to 24 h post treatment) in larval homogenates of topically treated larvae was the parent, spinosyn A [53, 54]. In contrast, these same larvae readily metabolized the acaricide fenazaquin [3, 53], clearly demonstrating that H. virescens larvae have the capacity to metabolize xenobiotics. Further, studies with H. virescens larvae highly resistant to spinosad [55] also found no evidence for metabolism of spinosyn A [56, 57]. 

An endocrine role has also been postulated in some species (84). Injection of teratocytes from the braconid parasitoid M. croceipes into larvae of the tobacco budworm, Heliothis virescens, caused an elevation of the ecdysteroids, an increase in JH levels and a decrease in the JH esterase activity in the host (85, Dahlman, D. L. Arch. Insect Biochem. Physiol., in press). 

Riskallah, M. R., W. C. Dauterman and E. Hodgson. 1986a. Nutritional effects on the induction of cytochrome P-450 and glutathion transferase in larvae of the tobacco budworm, Heliothis virescens. Insect Biochem. 16 491-499. 

During the 1970 s the USDA Nicotiana tabacum germplasm collection was evaluated in field plots at the Clemson University Pee Dee Research and Education Center, Rorence, SC for their resistance to the tobacco hornworm, Manduca sexta (L,) (1), and the tobacco budworm, Heliothis virescens (F.) (2). During this investigation a large variation in leaf trichome types and density was observed. Johnson et al. (3,4) classified the major trichome types from the various tobacco types as simple trichomes without exudates, glandular trichomes without exudates, glandular trichomes with exudates, and... 

Thiamethoxam has been reported to yield 7V-desmethyl thiamethoxam as well as clothianidin, the latter representing the dominant product 19). The metabolic conversion of thiamethoxam to clothianidin has been implied for its toxicology. To address this claim, we conducted an analytical study in which a 1000 ng (1 il dose of 1000 ppm) dose of thiamethoxam was injected into tobacco budworm Heliothis virescens 5 instar larvae and symptoms monitored at time points of 13, 30, 60 and 120 minutes after exposure. Symptoms of thiamethoxam toxicity were reliably observed 30 minutes after injection thus this time period was chosen for further experiments. Symptoms recorded were uncoordinated locomotion and rapid mandibular motion at a frequency of 3-4 jaw movements per second. 

TBW = tobacco budworm, Heliothis virescens BAW = beet armyworm, Spodoptera exigua DBM = diamondback moth, Plutella xylostella ppm = parts per million... 

Berge, M. A., G. A. Rosenthal, and D. L. Dahlman, Tobacco budworm, Heliothis virescens [Noctuidae] resistance to L-cana-vanine, a protective allelochemical, Pesticide Biochem. Physiol., 25, 319-326 (1986). 

---