黑龙江省3种林木对美国白蛾的适生性

为明确黑龙江省乔灌木树种对美国白蛾的适生性, 本试验选取水曲柳、白桦、榆叶梅3种林木的叶片于室内饲养美国白蛾4~6龄幼虫, 研究幼虫取食量及生长发育情况。结果表明:取食3种林木叶片的美国白蛾4龄幼虫累计死亡率差异不显著(P>0.05), 5、6龄幼虫累计死亡率由高到低为榆叶梅>白桦、水曲柳(P<0.05); 取食榆叶梅叶片的美国白蛾幼虫发育到6龄时全部死亡, 而取食水曲柳、白桦叶片的幼虫能完成生活史。美国白蛾4龄幼虫取食量由大到小为水曲柳>白桦、榆叶梅(P<0.05), 5龄的为水曲柳>白桦>榆叶梅(P<0.05), 6龄的为水曲柳>白桦(P<0.05)。美国白蛾4、5龄幼虫龄期长短顺序为榆叶梅、白桦>水曲柳(P<0.05), 取食水曲柳和白桦的美国白蛾6龄幼虫龄期长短差异不显著(P>0.05); 成虫期长短顺序为水曲柳>白桦(P<0.05), 而幼虫期和蛹期长短顺序与成虫期相比正相反(P<0.05)。取食水曲柳、白桦叶片的美国白蛾化蛹率、羽化率、产卵量及幼虫生长指数、蛹生长指数差异均不显著(P>0.05)。说明水曲柳和白桦为美国白蛾潜在适生寄主, 榆叶梅不适合其生长; 与白桦相比, 美国白蛾更喜欢取食水曲柳叶片, 且成虫寿命更长。这为预防美国白蛾传入定殖潜在适生树种、有针对性地采取措施保护黑龙江省林木提供理论依据。

Adaptability of three tree species in Heilongjiang province to Hyphantria cunea

In order to determine the adaptability of trees and shrubs in Heilongjiang province to Hyphantria cunea, the leaves of three tree species, Fraxinus mandshurica, Betula platyphylla and Amygdalus triloba, were used to raise the 4th-to 6th-instar larvae of H.cunea in the laboratory. The growth and development and the feeding amount of H.cunea larvae were studied. The results showed that there was no difference in the cumulative mortality of the 4th-instar larvae fed with the leaves of three tree species (P>0.05). The cumulative mortality rate of the 5th-instar larvae from high to low was A.triloba, B.platyphlla and F.mandshurica (P<0.05). All H.cunea larvae fed with A.triloba leaves died during the 6th-instar larvae, while H.cunea larvae fed with F.mandshurica and B.platyphlla leaves could complete their life cycle. The order of the average values of the 4th-instar food intake on the three tree species from high to low was F.mandshurica, B. platyphlla and A.triloba (P<0.05), while the order for the 5th-instar was F. mandshurica, B. platyphlla and A.triloba (P<0.05). The 6th-instar food consumption fed with F.mandshurica leaves was more than that with B.platyphlla leaves (P<0.05). The developmental durations of the 4th-and 5th-instar larvae fed with A.triloba and B.platyphlla leaves were longer than that with F.mandshurica leaves (P<0.05), and there was no difference between the developmental durations of the 6th-instar larvae feeding on B.platyphlla leaves and F.mandshurica leaves (P>0.05). The average value of adult period of H.cunea fed with F.mandshurica was longer than with B.platyphlla (P<0.05), but the larval and pupal periods were the reverse (P<0.05). There were no differences in the pupal rate, emergence rate, egg number laid by adults, larval growth index and pupal growth index of H. cunea feeding on F.mandshurica and B.platyphlla (P>0.05). This study suggested that F.mandshurica and B.platyphlla were potentially suitable hosts for H. cunea, but A.triloba was not suitable for its growth. H. cunea larvae preferred F. mandshurica to B. platyphlla leaves, and the adult longevity fed with F.mandshurica leaves was longer than that with B.platyphlla leaves. These results provided a theoretical basis for preventing the invasive H. cunea from colonizing potentially suitable species and for taking targeted measures to protect trees.