POSTEMBRYONIC GROWTH AND DEVELOPMENT OF F1 AND F2 TOBACCO BUDWORMS (LEPIDOPTERA: NOCTUIDAE) FROM PARTIALLY STERILE MALES

1972 ◽  
Vol 104 (2) ◽  
pp. 165-172 ◽  
Author(s):  
F. I. Proshold ◽  
J. A. Bartell

AbstractTobacco budworms, Heliothis virescens (F.), with inherited sterility caused by irradiation of the male parent were smaller than progeny from normal parents and developed more slowly throughout the larval and pupal periods. In the second generation the population segregated into two groups, those with normal and those with delayed development. Also, when the P1 male received 15.0 krad, 8% of the F1 larvae had more than the normal five instars. Moreover, when those F1 progeny that had only five larval instars were outcrossed to normal moths, this tendency for supernumerary molts increased nearly 3-fold. The slower development of progeny of treated moths would have to be considered in field tests made to evaluate the effect of inherited sterility on the tobacco budworm. However, with continuous release of irradiated males, the delayed development or smaller size of the progeny should not lessen the possibility that this method could successfully suppress field populations.

2019 ◽  
Vol 19 (3) ◽  
Author(s):  
Marisa Nardiello ◽  
Rosanna Salvia ◽  
Andrea Scala ◽  
Carmen Scieuzo ◽  
Sabino Aurelio Bufo ◽  
...  

Abstract Prothoracicotropic hormone (PTTH) is a neuropeptide that triggers a cascade of events within the prothoracic gland (PG) cells, leading to the activation of all the crucial enzymes involved in ecdysone biosynthesis, the main insect steroid hormone. Studies concerning ecdysteroidogenesis predicted PTTH action using brain extract (BE), consisting in a complex mixture in which some components positively or negatively interfere with PTTH-stimulated ecdysteroidogenesis. Consequently, the integration of these opposing factors in steroidogenic tissues leads to a complex secretory pattern. A recombinant form of prothoracicotropic hormone (rPTTH) from the tobacco budworm Heliothis virescens (F.) (Lepidoptera: Noctuidae) was expressed and purified to perform in vitro tests in a standard and repeatable manner. A characterization of rPTTH primary and secondary structures was performed. The ability of rPTTH and H. virescens BE to stimulate ecdysteroidogenesis was investigated on the third day of fifth larval stage. rPTTH activity was compared with the BE mixture by enzyme immunoassay and western blot, revealing that they equally stimulate the production of significant amount of ecdysone, through a transduction cascade that includes the TOR pathway, by the phosphorylation of 4E binding protein (4E-BP) and S6 kinase (S6K), the main targets of TOR protein. The results of these experiments suggest the importance of obtaining a functional pure hormone to perform further studies, not depending on the crude brain extract, composed by different elements and susceptible to different uncontrollable variables.


1988 ◽  
Vol 23 (3) ◽  
pp. 223-228 ◽  
Author(s):  
M. R. Bell

A greenhouse test and two field tests were conducted to determine if a dye method of marking the fat body using Red Calco Dye could be used to identify adult tobacco budworms, Heliothis virescens (F.), and the bollworms, H. zea (Boddie), that had developed as larvae primarily on Geranium dissectum L. In a greenhouse trial, 73% of 22 adult tobacco budworms contained internal red dye after larvae fed on geranium plants treated with 10 ml of a dye mixture per plant (1% dye + 9% crude cottonseed oil + 90% water). No dye was detected in adults from larvae reared on untreated plants. One field was first infested with neonate tobacco budworms, and then treated with the dye mixture. Marked adults were caught in blacklight traps over a 13-day period. A second field of wild geranium, being ca. 11% of the total geranium in the immediate area, was treated with the dye mixture without artificial infestation. From the first to last marked adult caught in pheromone traps, 6.8% of the bollworms and 8.3% of the tobacco budworms contained internal red dye.


1991 ◽  
Vol 26 (2) ◽  
pp. 281-286
Author(s):  
Marion L. Laster ◽  
Earl A. Stadelbacher

The sexual attractancy of female Heliothis virescens (F.) which had been cultured in the laboratory for 40 generations and of hybrid and backcross females (H. subflexa ♀ X H. virescens ♂) was determined and compared with the attractancy of wild female H. virescens. In field tests, females reared (< 1 generation) from field-collected larvae were significantly (P ≤ 0.05) less attractive to wild males than were females reared in the laboratory for 40 generations (HVL-40), but the attractancy of females reared in the laboratory for 1 or 41 generations did not differ significantly. The attractancy of H. virescens females from generations 40, 41 and BC females from generations 41, 42 or 179, 180 did not differ significantly in any of five tests, except in test three, where more wild males were attracted by HVL-40 than by BC-41 females. Continuous backcrossing of the female hybrid (180 generations) did not affect the attractivity of the female to the wild males. The attractancy of lab-reared H. virescens (except for generation 40) or hybrid BC virgin females, regardless of generation, to wild H. virescens males was not significantly different from that of the synthetic female sex pheromone Z-11-Hexadecenal: Z-9-tetradecenal (14.6:1). The data indicate the attractancy of H. virescens and BC virgin females to wild males may be enhanced by continuous laboratory rearing. These findings are important in population dynamic studies in which lab-reared females are used and in determining the ratio of BC to wild H. virescens females needed to suppress a given population of H. virescens.


1988 ◽  
Vol 23 (3) ◽  
pp. 229-233
Author(s):  
J. A. Joyce ◽  
R. J. Ottens ◽  
G. A. Herzog ◽  
M. H. Bass

Laboratory cultures of field-collected larval tobacco budworm, Heliothis virescens (F.), beet army worm, Spodoptera exigua (Hübner), and fall armyworm, S. frugiperda (J. E. Smith) were bioassayed for response to three pyrethroids in combination with piperonyl butoxide (PBO), or MGK-264. The greatest synergistic effects were seen in S. exigua which also displayed the greatest tolerance to pyrethroids without synergists. The highest SR50 (synergist ratio) value for S. exigua was 22.1 with fenvalerate-PBO mixed in a ratio of 1:5, the highest for S. frugiperda was 4.6 with fenvalerate-MGK-264 1:5, and the highest for H. virescens was 1.3 with permethrin-MGK-264 1:5 or with fenvalerate-PBO 1:5.


1989 ◽  
Vol 24 (4) ◽  
pp. 539-544 ◽  
Author(s):  
Abdul K. Mohamed ◽  
Jen-Rong Yang ◽  
Fred R. S. Nelson

Laboratory studies were conducted to determine the response of healthy and cytoplasmic polyhedrosis virus (CPV) infected Heliothis virescens (F.) larvae to LD50 of methomyl and methyl parathion. Methomyl-CPV combination adversely affected pupal weight and fecundity of the female. The effect of this interaction was synergistic. Exposure of CPV infected larvae to LD50 of methomyl resulted in a mean female pupal weight of 243 mg and a fecundity of 382 per female moth. These values were significantly lower than those of all other treatments. In contrast methyl parathion-CPV combinations did not result in a significant reduction in pupal weight as compared to the control. Adult emergence and egg hatch were not affected.


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