黄曲条跳甲为害引起的菜心价值损失及防治指标研究

Studies on the Influence of Phyllotreta striolata on the Value Loss of Brassica campestrist and the Economic Thresholds

测定了菜心不同生育期黄曲条跳甲Phyllotreta striolata(Fabricius)成虫数量、成虫咬食所造成的叶片孔洞数与菜心价值损失率的关系,并以成虫数量和叶片上的孔洞数为标准,制定了黄曲条跳甲在菜心上的防治指标.结果表明,在菜心的苗期和生长期,随着黄曲条跳甲成虫数量的增加,菜心叶片孔洞数和价值损失率逐渐增大.苗期和生长期,每株菜心上的成虫数(X)与每株菜心叶片上的孔洞数(Z)均呈正相关,其回归方程分别为:Z=5.321 7+90.905 7X和Z=7.436 2+63.791 8X.苗期和生长期,Z与菜心价值损失率(Y)均呈正相关,其回归方程分别为:Y=0.037 5+0.004 3Z和Y=0.007 9+0.002 9Z.以成虫数量作为防治指标时,菜心苗期和生长期的防治指标分别为0.28和0.74头/株.以菜心叶片上的孔洞数作为防治指标时,苗期和生长期的防治指标分别为32和55个/株.

The vegetables value loss caused by the yellow striped flea beetle,Phyllotreta striolata,at the different growth stages of Brassica campestrist was studied.The results showed that the value loss increased with the number of inoculated yellow striped flea beetle adults.The quantitative relation between the number of yellow striped flea beetle adult（X） and the number of feeding holes on the leaves（Z）in the seedling stage and growing stage could be expressed by equations Z=5.321 7＋90.905 7X and Z=7.436 2＋63.791 8X respectively.The quantitative relation between the number of feeding holes on the leaves（Z） and the percentage of the value loss（Y） in the seedling stage and growing stage could be expressed respectively by equations Y=0.037 5＋0.004 3Z and Y=0.007 9＋0.002 9Z.Two economic thresholds were put forward for B.campestris in seedling stage and growing stage according to the density of P.striolata,which were 28 and 74 adults per 100 plants,respectively.Based on the feeding holes,the economic thresholds could be figured as 32 and 55 holes per 100 plants in seedling stage and growing stage respectively.