Effects of Three Insect Growth Regulators onEncarsia formosa(Hymenoptera: Aphelinidae), an Endoparasitoid ofBemisia tabaci(Hemiptera: Aleyrodidae)

Abstract

Insect growth regulators (IGRs) disrupt the normal activity of the endocrine or hormone system of insects, affecting the development, reproduction, or metamorphosis of the target insects, and normally causing less detrimental effects to beneficial insects. The effects of three IGRs (pyriproxyfen, fenoxycarb, and buprofezin) on Encarsia formosa Gahan, an endoparasitoid of whiteflies, were determined using B. tabaci as a host. We assessed the effects of the IGRs on parasitoid's larval development, pupation, emergence, and contact effects of the dry residues on plant leaf and glass vial surface on adult mortality and parasitism. When the three IGRs were applied at larval stage, no or few larvae pupated in the pyriproxyfen treatments and the highest concentration of fenoxycarb, and a majority of larvae pupated in the buprofezin treatments; of those pupated, 62.3-88.1% became adults. When the IGRs were applied at the pupal stage, 2.3-17.5% developed to adults in the pyriproxyfen treatments, 59.7-89.0% in the fenoxycarb treatments, and 58.4-83.6% in the buprofezin treatments. The leaf residues of the IGRs had no appreciable effects on adults, whereas the residues on glass vial caused significantly lower adult survival than on plant leaves. The residues of pyriproxyfen and fenoxycarb slightly reduced parasitism as compared with buprofezin and controls. However, the rates of parasitoids that became adults were significantly lower, especially in the pyriproxyfen treatments. According to the standards of International Organization of Biological Control (IOBC), pyriproxyfen was harmful, while fenoxycarb and buprofezin were slightly or moderately harmful to larvae and harmless to E. formosa pupae.

Impairment of Development and Reproductivity of the Egyptian cotton leafworm Spodoptera littoralis Boisduval (Noctuidae: Lepidoptera) by Cycloheximide.

“…In the present study on S. littoralis, cycloheximide exerted a suppressive action on pupation, since the pupation rate was drastically regressed after topical treatment of the newly moulted last instar larvae with the lower three doses (120, 60 and 30 µg/larva). This results was, to a great extent, consistent with those reported results of regressed pupation rate of some insects by various IGRs, such as the diamondback moth Plutella xylostella by hexaflumuron (Mahmoudvand et al, 2012); S. littoralis by novaluron (Ghoneim et al, 2015); G. pyloalis by lufenuron (Aliabadi et al, 2016) and fenoxycarb (Singh and Tiwari, 2016); the whitefly parasitic wasp Encarsia formosa by pyriproxyfen and fenoxycarb (Wang and Liu, 2016); P. gossypiella (Ghoneim et al, 2017a) and P. unionalis (Ghoneim et al, 2017b) by Novaluron. In the current study, also, cycloheximide exhibited weak antimorphogenic efficiency on S. littoralis because some deformed pupae were produced only at 120µg/larva.…”

Deteriorating Effects of Methoxyfenozide on Survival, Development and Metamorphosis of the Olive Leaf Moth, Palpita unionalis (Hübner) (Lepidoptera: Pyralidae).

“…xylostella by hexaflumuron (Mahmoudvand et al, 2012); S. littoralis by novaluron (Ghoneim et al, 2015) and cyromazine (Tanani et al, 2015); G. pyloalis by lufenuron (Aliabadi et al, 2016) and fenoxycarb (Singh and Tiwari, 2016); Encarsia formosa by pyriproxyfen and fenoxycarb (Wang and Liu, 2016); P. gossypiella (Ghoneim et al, 2017a) and P. unionalis (Ghoneim et al, 2017b) by novaluron as well as P. gossypiella after treatment of 1-day old eggs with noviflumuron or novaluron (Hamadah and .…”

“…During the last few decades, a new class of comparatively safe compounds has been developed and known as insect growth regulators (IGRs) (Dhadialla et al, 1998;Khan and Qamar, 2012). IGRs are not directly toxic, but act selectively on the development, metamorphosis and/or reproduction of the target pest (Nicholas et al, 1999;Martins and Silva, 2004) owing to their disruptive effects on the normal activity of endocrine or hormone system of insects (Wang and Liu, 2016). Because of their desirable characteristics, such as potential action of the target pest, low toxicity to non-target organisms, less environmental pollution, high selectivity, and low impact on natural enemies, domestic animals and people, IGRs are used to control various insect pests and can assist in the development of sustainable agriculture (Wang and Wang, 2007;Taleh et al, 2015;Sabry and Abdou, 2016).…”

Enhancing "Psyttalia concolor" (Szépligeti) (Hymenoptera: Braconidae) in olive groves to increase biological control of the olive fruit fly = Incrementar la presencia de "Psyttalia concolor" (Szépligeti) (Hymenoptera: Braconidae) en los olivares para mejorar el control biológico de la mosca del olivo

“…Results with P. concolor indicate that fenoxycarb does not affect the longevity and emergence of parasitoid (Table 6.1., for more details see Jacas González, Bahena and Viñuela, 1998). Other studies obtained similar result and found that fenoxycarb was slightly harmful for other parasitoids, such as, Encarsia formosa (Hymenoptera: Aphelinidae) larvae (Wang and Liu, 2016). Another problematic feature of fenoxycarb is its low soil mobility, non-accumulation, and its quick breaking down in the environment (Michel, Krause and Buszewski, 2001).…”

“…Considering pyriproxyfen (group 7C, IRAC), another IGR, Abdallahi, Adán and Viñuela (2000) obtained slightly harmful effects in P. concolor mortality but harmless for the parasitoids reproduction (Table 6.1.). In contrast, pyriproxyfen caused high levels of mortality on Eretmocerus eremicus (Hymenoptera: Aphelinidae) (Hoddle et al, 2001) and was harmful to Encarsia formosa (Hymenoptera: Aphelinidae) larvae and moderately harmful to pupae (Wang and Liu, 2016). However, the application of pyriproxyfen highly decreases the rates of the mature and emerged parasitoids (Wang and Liu, 2016).…”