Effect of several botanical edible oils on the conidia germination of Nomuraea rileyi

Abstract:

[Objective] In order to find out the difference of conidia germination rate, germination speed of Nomuraea rileyi strain Nr0815 which was isolated from the infected larva of Argyrogramma agnata Staudinger (Lepidoptera: Noctuidae) in the eight botanical edible oils at different temperatures. [Methods] The absorbance of Nr0815 conidia in eight botanical edible oils was measured by ultraviolet spectrophotometer, the conidia germination rate in different oils and the germination speed at different observation period within 72 h at different temperatures were observed using slide germination method. [Results] The conidia of N. rileyi showed a good dispersion in the tested botanical edible oils. The conidia of N. rileyi in all botanical edible oils was normally germinated at the temperature ranged from 10 to 30 °C, among of them, the maximum accumulative germination rate of N. rileyi conidia was in the soybean oil, germination speed in other oils increased with the extend of time within 72 h except for that in the soybean oil and rape oil at 23 °C, and the maximum germination speed was at 48-72 h. The germination speed was slowest under 10 °C, and it began to germinate after 48 h. From the development of germ tube, the germ tube length of N. rileyi in soybean oil was the longest at 23 °C, the length was (24.89±1.04) μm, and the minimum germ tube length was from that in the sunflower seed oil, the length was (9.10±1.00) μm. [Conclusion] The temperature and botanical edible oil affected the conidia germination of N. rileyi, and the result provided theoretical basis for the development and utilization of conidia oil formulation of N. rileyi.