Forecast Methods Of Dioryctria Rubella And Conogethes Punctiferalis

This article studied forecasting and predicting of D.rubella and C.punctiferalis through ways of field investigation, attracting methods'screening, rearing in laboratory, attraction of synthetic sex pheromone, light-traps and finally got the forecast methods. On the basis, the researchers proceeded field examinations and gave referenced suggestions to correlative departments. The results are summarized as follows:(1)Investigation results of insect damage: The most serious damage of D.rubella occurred in Nanjing Forestry University-owned forestry farms and the least one occurred in Forest Farm of Maanshan. The average percentage of damage of Pinus taeda was 44.4%, of which Pinus massoniana was 31.6%. The average percentage of damage of primary branches and the average rate of damaged shoots was 62.1% and 8.49% respectively. The average rate of damaged shoots negatively related to tree height and diameter. Only two areas had the damage of C.punctiferalis. The damage rate of Forest Farm of Banta was 87.6% and that of Shuangpaishi pinewood was 45.8%. The average rate of damaged shoots was 7.78% in Shuangpaishi pinewood. Every pine had 2.55 wormy bags with silk. Every wormy bag averagely had 6.95 larvae. And every pine averagely had 16.45 larvae. The average rate of damaged shoots negatively related to tree diameter.(2)The black light luring was significant on C.punctiferalis. As to D.rubella, the sex attractant alluring was the best with black light lamp lure in second. The effect of water basin was better than that of trapping board. The rest methods didn't reach desired results, which needs further studies.(3)Through surveying pupation progress with the addition of corresponding development period in filed the author obtained following conclusions. The peak period of the overwintering adults was from May 18th to May 25th, which of the first generation was from July 6th to July 13th.The period of rape large bloom was coincident simulated with the peak period of winter generation larval harm. Established forecasting model with occurrence quantity of adults and damage's relation, which was y₁=13.7+1.638x, y₂=0.174+0.019x. On the basis of lamp luring, the overwintering adults of C.punctiferalis initially appeared in late May, and the peak period of adults was from late July to late August.(4)The forecasting occurrent date of D.rubella was coincident simulated with the real results and the error was wihin 5 days. The forecast of amount was significantly correlated to the real facts. Tests showed the results of forecast had good reliability and validity.