Effect of juvenile hormone and pyriproxyfen treatments on the production ofSpodoptera lituranuclear polyhedrosis virus

Abstract

Efficient production is essential for developing baculoviruses into marketable bioinsecticides. In this study, we evaluated how juvenile hormone (JH) III and the JH analog pyriproxyfen affected the production efficiency of Spodoptera litura (Fabricius) (Lepidoptera: Noctuidae) Nucleopolyhedrovirus (SpltNPV) in SpltNPV-inoculated early sixth instars. Both the JH III and pyriproxyfen treatments significantly enhanced the body size and weight of S. litura, which resulted in a 1.5-to 2-fold increase in the production of occlusion bodies (OBs). The OBs obtained from JH-and pyriproxyfen-treated larvae were as pathogenic as those produced in untreated larvae. More importantly, JH-or pyriproxy-fen-treated larvae consumed less than twice the amount of food consumed by two untreated larvae. These results indicate that JH and pyriproxyfen treatments improve the production efficiency of SpltNPV in S. litura. SpltNPV infection affected the development of S. litura not only as larvae, but also during subsequent growth stages and generations.

Fenoxycarb exposure affects antiviral immunity and HaNPV infection in the cotton bollworm, Helicoverpa armigera

“…These results corroborated a previous report that showed treatment of H. armigera with exogenous JH increased HaNPV concentration 47 . Also, production of baculovirus occlusion bodies (OB) in Spodoptera lituralis larvae was increased following treatment with JH and pyriproxyfen 56 . According to this finding, we examined whether suppression of antiviral immunity by feeding on food containing fenoxycarb could affect susceptibility of H. armigera larvae to HaNPV.…”

“…Our results also indicated that feeding on diet containing fenoxycarb for 48 and 96 h could increase the mortality of H. armigera larvae by HaNPV. There are two possible explanation for how JH could interfere with viral pathogenicity: first, fenoxycarb suppresses antiviral immunity and as a consequence virus have more opportunity for replication; and secondly, JH prolongs the larval stage and enhances feeding, thus leading to bigger larvae and higher virus yield 56 …”

Effect of gamma irradiation on the susceptibility of the cotton leaf worm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) to the infection with nucleopolyhedrosis virus

“…The NPV mass production was influenced by several factors such as virus concentration, larval age at virus treatment, temperature, and harvesting time (Cherry et al 1997;Subramanian et al 2006;Rios-Velasco et al 2012). Furthermore, numerous techniques have been proposed to improve the production of baculoviruses such as juvenile hormones used for increasing the production of Spodoptera exigua multicapsid NPV (SeMNPV) (Lasa et al 2007) and for the production of Spodoptera litura NPV (SpltNPV) (Liao et al 2016). In addition, Elvira et al (2010) developed a low-cost diet for the large scale in vivo production of SeMNPV.…”

Pareto-efficient biological pest control enable high efficacy at small costs

“…These assumptions are reflected in the following conditions on the parameters, a S ≫ a I , c S ≫ c I and d S < d I . In Table 1 we state units and numerical values for all model parameters based on published papers (Ball et al 2000;Ruiz-Nogueira et al 2001;Xiao and Van Den Bosch 2003;Dale 2006;Liu et al 2015;Liao et al 2016). While the techniques developed in this paper are independent of this special parametrization, the determined control strategies do depend on our chosen parametrization.…”