Heliothis virescens larvae

Electrophysiological evidence indicates that spinosyns can alter nicotinic currents in neuronal cell bodies from CNS of the American cockroach [P. americana (L)j. The effect is correlated with toxicity to neonate Heliothis virescens larvae. It can be su ested that the spinosyns affect nAChR and GABA receptors through a so-called undetermined mecdianism and differ from that of neonicotinoids... 

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]. 

Fura-2 fluorescence measurements were done on isolated neuronal cell bodies obtained from fifth instar Heliothis virescens larvae as described previously (15). The fluorescence emission was detected using a Fura filter set (DCLP 410, LP 470). 

Nettles, W. C. and Burks, M. L. (1975) A substance from Heliothis virescens larvae stimulating larviposition by females of the tachinid, Archytas marmoratus. J. Insect Physiol., 21, 965-78. 

Navon, A., J.D. Hare B.A. Federici. 1993. Interactions among Heliothis virescens larvae, cotton condensed tannin and the CrylA(c) / /to-endotoxin of Bacillus thuringiensis. J. Chem. Ecol. 19 2485-2499. 

Jurat-Fuentes, J.L. and M. Adang. 2006. Cry toxin mode of action in susceptible and resistant Heliothis virescens larvae. J. Invertebr. Pathol. 92 166-171. 

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. 

Table IV. Growth-Inhibitory Activity of Some Bioactive Constituents Derived from Geranium viscosissimum var. viscosissimum Fed in an Artificial Diet to First-Instar Larvae of Heliothis virescens...

Oil Limonoids Fed in an Artificial Diet to Flrst-Instar Larvae of Heliothis virescens... 

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... 

Table IV. Reduced Rate of Acetylcholinesterase Phosphorylation in Resistant Tobacco Budworm Larvae, Heliothis virescens...

Manduca sexta and Pieris rapae, are sensitive to topically applied a-ter-thienyl (3) in the presence of light, whereas others such as Heliothis virescens are insensitive. a-Terthienyl (3) also showed potent activity (LD50 19 ppb) towards the light-exposed water-living larvae of the mosquito Aedes aegyptii [98]. 

Bt used in spray-on formulations is, perhaps, the most successful biopesticide. Reasons for Bt s success include ease of handling and a very high specific activity against sensitive insects. For example, a Bt insecticidal protein called CrylAc has a LCjq on Heliothis virescens neonate larvae as low as 0.07 ppm [10]. However, most individual Bt insecticidal proteins have a narrow activity spectrum. As mentioned, CrylAc is very active against H. virescens, while another Bt toxin called CrylCa is not. CrylCa is active against Spodoptera exigua, but CrylAc is not. This is perhaps... 

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. 

Derivatized Tetranortriterpenoids from Azadirachta indica and Melia azedarach Fed in Artificial Diet to FirsMnstar Larvae of Heliothis virescens. 

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. 

Homeosoma electellum) contain high concentrations of tra-chyloban-19-oic acid (70) and ( —)-16-kauren-19-oic acid (71) in their florets. As sunflower florets that contain only small amounts of these compounds are a major portion of the diet of first instar larvae of this insect, it is likely that these acids serve as feeding inhibitors. At the 1% level, both kaurenoic and trachylobanoic acids decreased the growth of sunflower moth larvae and tobacco budworm (Heliothis virescens) by about 50%. At the 0.5% level, both reduced larval growth of the cotton bollworm and the pink bollworm to less than 5% (Fig. 22.23) (Mabry and Gill, 1979). The Z-and -isomers of (- )-ozic acid (72) have been isolated from Helianthus occidentalis and may be associated with resistance to insect attack (Stipanovic et al., 1979). 

Jackson DM, Johnson AW, Stephenson MG (2002) Survival and development of Heliothis virescens (Lepidoptera Noctuidae) larvae on isogenic tobacco lines with different levels of alkaloids. J Econ Entomol 95 1294-1302... 

Figure 2. Symptoms of 2nd instar larva of Heliothis virescens treated with AcAalT. The larva on the right shows typical contraction of the larval segments associated with the paralyzing effects after exposure with the recombinant virus AcAalT. The larva on the left was treated at the same time with wild-type AcNPV and shows no signs of infection. (Picture by Dr. Michael P. Parrella, Department of Entomology, UC Davis).

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