Chemical pesticides have been used for pest control for many decades, but they cause serious problems, including insecticide resistance, secondary pest resurgence, and negative environmental impacts. Therefore, sustainable alternatives to chemical pesticides are necessary for pest control. Entomopathogenic fungi (EPF) are natural epizootic pathogens of insects, and some of them have been used as microbial biocontrol agents. Herein, we attempted to construct an entomopathogenic fungal library (EFLib) via the “Tenebrio molitor pathogenicity-based fungal collection method (TmPC)” to select EPF for control of the serious agricultural pest Spodoptera litura. A total of 172 soil samples were collected in northern and central Taiwan for the EFLib construction. The isolation efficiency of TmPC was 64.02%. The EFLib consisted of 101 isolates and was designated as the National Chung Hsing University (NCHU) EFLib. Among these isolates, 26 showed high virulence (mortality = 100%) to T. molitor larvae. Based on the results of molecular identification, the highly virulent isolates belonged to seven genera, including Beauveria, Clonostachys, Fusarium, Cordyceps, Penicillium, Purpureocillium, and Metarhizium. To evaluate the potential of these isolates for Spodoptera litura control, 12 isolates were selected for pathogenicity screening against S. litura larvae. A total of six EPF isolates belonging to the genera Beauveria and Metarhizium showed rapid eradication of the S. litura larvae. To rank the potential of these fungal strains for pest management, the six isolates were subjected to thermotolerance and conidial production assays, and a novel effective conidia number (ECN) formula was applied. The results indicated that the ECN index of Beauveria australis (NCHU-113) was much higher than that of Metarhizium isolates. However, among the Metarhizium isolates, NCHU-95 showed the highest ECN index. Altogether, NCHU-69 and NCHU-113 should be further tested in field trials. To our knowledge, this is the first attempt to integrate pathogenicity or virulence and ECN data into EPF screening and ranking, providing a baseline for mass selection of potential EPF strains for further applications.

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This study was conducted to further understand the biology of Eutetranychus africanus Tucker, a newly invasive pest mite in Taiwan that can cause serious damage to papaya. We report the life history of E. africanus on papaya in laboratory conditions at 12, 17, 22, 27 and 32 ± 0.5 °C, with 70 ± 5 % relative humidity and a photoperiod of L12: D12. Eggs did not hatch at 12 °C. Both developmental duration and longevity were significantly shortened with the increase of temperature. The longest and shortest developmental durations of the immature stage were 37.28 days at 17 °C and 8.70 days at 32 °C, respectively. The longevity of both sexes varied similarly with the change in temperature, with shorter lifespan in males: Females survived for 3.64 days (shortest) at 32 °C to 17.50 days (longest) at 17 °C, whereas males survived for 11.00 days (longest) at 17 °C to 2.57 days (shortest) at 32 °C. The differences in fecundity were significant among all tested temperatures, with 17.61 eggs/female at 27 °C being the highest. The low developmental threshold and thermal summation of the full immature stage were 11.48 °C and 163.93 degree-days, respectively. In two-sex life table analysis, population parameters were significantly affected by temperature except the net reproduction rate. The highest intrinsic rate of increase was 0.1221 day−1 at 27 °C; the average generation time was the shortest (12.61 days) at 32 °C and the longest (48.70 days) at 17 °C. The highest net reproduction rate was 5.06 eggs/female at 27 °C. This report contributes background knowledge to the management of the damage caused by E. africanuson papaya.This study was conducted to further understand the biology of Eutetranychus africanus Tucker, a newly invasive pest mite in Taiwan that can cause serious damage to papaya. We report the life history of E. africanus on papaya in laboratory conditions at 12, 17, 22, 27 and 32 ± 0.5 °C, with 70 ± 5 % relative humidity and a photoperiod of L12: D12. Eggs did not hatch at 12 °C. Both developmental duration and longevity were significantly shortened with the increase of temperature. The longest and shortest developmental durations of the immature stage were 37.28 days at 17 °C and 8.70 days at 32 °C, respectively. The longevity of both sexes varied similarly with the change in temperature, with shorter lifespan in males: Females survived for 3.64 days (shortest) at 32 °C to 17.50 days (longest) at 17 °C, whereas males survived for 11.00 days (longest) at 17 °C to 2.57 days (shortest) at 32 °C. The differences in fecundity were significant among all tested temperatures, with 17.61 eggs/female at 27 °C being the highest. The low developmental threshold and thermal summation of the full immature stage were 11.48 °C and 163.93 degree-days, respectively. In two-sex life table analysis, population parameters were significantly affected by temperature except the net reproduction rate. The highest intrinsic rate of increase was 0.1221 day−1 at 27 °C; the average generation time was the shortest (12.61 days) at 32 °C and the longest (48.70 days) at 17 °C. The highest net reproduction rate was 5.06 eggs/female at 27 °C. This report contributes background knowledge to the management of the damage caused by E. africanus on papaya.

A new isolate of the entomopathogenic nematode, Steinernema taiwanensis n. sp., was isolated from soil in Pingtung County, Taiwan. This new species could be characterized and distinguished from other related species by its morphological characters, morphometrics, and phylogenetic analysis. The body length and distance from anterior end to nerve ring of infective juveniles is 1012 (983–1045) µm and 124 (120–127) µm, lateral field formula 2, 6, 7, 8, 2, and the tail length 90 (79–96) µm without dorsal constriction in tail region. The first generation males of S. taiwanensis n. sp. are characterized by spicule shape, smooth blade tip, 23 genital papillae (11 pairs and 1 single papilla), spicule length of 94 (89–99) µm and gubernaculum length of 68 (65–70) µm. Females from the first generation of S. taiwanensis n. sp. have no epiptygmata and a slightly developed post-anal swelling. Phylogenetic analysis of ITS and D2D3 regions of rDNA showed that S. taiwanensis n. sp. belongs to the Longicaudum-clade and comprises a monophyletic group with S. guangdongense and S. longicaudum. The new isolate is described as a novel species according to morphological and phylogenetic analyses.

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