Study On The Bionomics And Key Control Techniques Of Two Species Of Pine Tip Moths

Dioryctria rubella and Conogethes punctiferalis were studied in this paper. This paper reported the bionomics, development of larval artificial diets, olfactory responses of adults to different kinds of pine branches and the screening of highly virulent strains of entomopathogenic fungi. The main conclusions were as follows:1. D. rubella had 2～3 generations per year in Nanjing and overwintered as larvae in branches damaged. The sex ratio (female: male) was 5:9. The pupation rate and emergence rate were 47.30 % and 71.43%, respectively. No significant differences in longevity were observed among the adults feeding on water, 10% honey solution or 10% sugar and vinegar liquid under laboratory conditions. Adults did not exhibit strong phototaxis, and the mean moth catches per night was 19 in a blacklight trap. D. rubella could cause more severe damage to Pinus taeda than to P. massoniana and P. thunbergii. Acarina and Staphylinidae were the dominant populations in the pine shoot tunnel bored by D. rubella.2. An artificial diet specifically suitable for larvae of D. rubella was developed, which was made of pine branch powder, casein, wheat germ, soybean flour, cane sugar, glucose, choline chloride, vitamin C, and so on.3. The olfactory responses of adults of D. rubella to different kinds of pine branches have been studied by means of Y-tube olfactometer. The trend responses to healthy branches of P. taeda and P. massoniana were stronger than that of P. thunbergii. Moreover, the trend response to CH2Cl2-extracts of bored dead branches of P. taeda was stronger than that of unbored dead branches and healthy branches.4. Beauveria bassiana strain B15 showed the highest virulence towards larvae of D. rubella with a mortality of 90%, and the LT50 was 6 d at concentration of 1×107 conidia/mL.5. C. punctiferalis had 3 generations per year in Nanjing and overwintered as larvae in the needles-twisted bag. The percentage of insect-invaded branches was 7.6 %, and the sex ratio (female: male) was 2: 3. Adults emerged mainly between 22:00pm～8:00am, and the emergence rate was 92.22 %. The date corresponding to the emergence of 50% total moths was May 11th. The longevity of adults was obvious significantly affected by adult nutritional conditions. Adults exhibited strong phototaxis, and the maximum moth catches per night was 418 in a blacklight trap.6. C. punctiferalis had the highest larval feeding preferences to P. thunbergii, while it had the least larval feeding preferences to P. taeda. Temperature and humidity affected the feeding behavior of larvae, but light did not. The contents of soluble sugars, protein, flavonoids and total phenol in three host plants, i.e., P. massoniana, P. taeda and P. thunbergii, were significantly different. Adults showed the strongest behavioural response to P. massoniana branches, less response to P. taeda branches, and the weakest response to P. thunbergii branches.