Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/8/2017
Publication Date: 2/1/2018
Citation: Weiler, L., Rooney, A.P., Behle, R.W., Muturi, E.J. 2018. Impact of Tolypocladium cylindrosporum (Hypocreales: Ophiocordycipitaceae) on eggs of Aedes aegypti and Aedes albopictus at low temperature. Meeting Abstract.
Technical Abstract: We examined the potential of Tolypocladium cylindrosporum IBT 41712 to infect eggs of Aedes aegypti Linnaeus and Aedes albopictus (Skuse) mosquitoes at low temperature (15 deg C). To determine the optimum temperature for the fungus, we cultured the fungus at eight temperatures (4, 12, 15, 21, 28, 33, 37 and 40 deg C) and measured the diametric growth. The optimum temperature for growth was 28 deg C since it had the highest diametric growth rate (2.1 ± 0.05 mm/day) and the fastest sporulation period (within 8-10 days of incubation). There was no fungal growth at the three highest temperatures (33, 37 and 40 deg C) but plates incubated at 33 deg C when shifted to optimal temperature (28 deg C) showed visible growth indicating that incubation at 33 deg C, the fungus remained viable. IBT 41712 successfully infected mosquito eggs at 15 deg C. Fungal treatment induced egg hatch on moist seed germination paper and this effect was more pronounced in Ae. aegypti compared to Ae. albopictus. When treated eggs were immersed in dH2O 21 days post treatment, larval hatch of both Ae. aegypti (control = 91%, 1 × 10**7 conidia/mL, fungal treatment = 0%) and Ae. albopictus (control = 85%, fungal treatment = 28%) was significantly lower in fungal treatment compared to the controls. The ability of the strain to grow in a wide temperature range, and effectively infect mosquito eggs and induce egg hatch at low temperature warrants further investigation for its potential as a mosquito control agent targeting eggs that overwinter or undergo long diapause.