胡瓜園瓜實蠅之棲羣密度與為害關係研究

Abstract

胡瓜瓜實大小與受瓜實蠅為害情形，無論就被害瓜率，被害瓜之產卵孔數或篩出之蛹數比較，均以中等瓜（重 0.2~0.59kg）為最顯著。於六處胡瓜園試驗結果，求得瓜園內瓜實蠅之誘殺蟲數（x）與鄰近作物上誘殺蟲數（Y1）間之相關方程式為Y1=4.77x +0.68(r =0.81）與被害瓜率（Y2）相關方程式為 Y2 = 0.57x + 3.21(r =0.79)，與每公斤被害瓜篩出之蛹數（Y3）相關方程式為 Y3 = 2.24x + 29.01 (r =0.83)，與每50個被害瓜產卵孔數（Y4）相關方程式為 Y4= 0.78x + 73.07 ( r = 0.55）。胡瓜園內瓜實蠅之棲羣密度由開花期逐漸增加，至瓜實成熟期達最高峰，鄰近作物上瓜實蠅之棲羣密度則由結瓜期逐漸增加，至採收後期達高峰。瓜園全面噴施福木松 33%乳劑、力拔山 50%乳劑及大滅松 44%乳劑等均能顯著的降低瓜實蠅密度及被害瓜率。 The midsize cucumber (0.2-0.59kg/fruit) which damaged by melon fly was conspi-cuously abundant with holes of oviposition and the number of pupa. The main experi-ment of relationship was tested in six cucumber orchards. Results indicated the regres-sion equation between the number of melon fly caught in cucumber orchard (x) and nearby plant (y1) was y1 =4.77x+0.68 (r = 0.81), x and the percentage of melons infes-tation which caused by melon fly (y2) was y2 =0. 57x+ 3.21 (r = 0.79), x and the number of pupae per Kg of damaged melon (y3) was y3 =2.24x+29.01 (r = 0.83), x and holes of oviposition per 50 melons which laid eggs by melon fly (y4) was y4 = 0.78x+73.07 (r = 0.55). The population density of melon fly in cucumber orchard increased from blossom stage and maximized at the harvest stage; In nearby plant, it increased from fruit stage to later harvest. The population density of melon fly and percentage of infestation can be decreased conspicuously, if sprayed insecticide such as Formothion 33% EC or Fenthion 50% EC or Dimethoate 44%EC on whole cucumber orchard.