甘藍主要害蟲在臺灣南部之發生消長

Abstract

在臺灣南部經3 年連續調查甘藍主要害蟲，結果得知常見者有9 種。（1）小菜蛾（Plutella zylostella）幾乎全年均有出現，其發生盛期由12 月至次年3 月，高峰都在2 月。其每年發生豐量受氣象因子影響，差異頗鉅，夏季降雨雖可影響其發生，但在春季微量降雨反可助長發生。（2）白粉蝶（Artogeia rapae crucivora）亦幾乎全年都有出現。一年有兩次發生盛期，一在2-5 月，最高峰多在4 月或3 月。另一次在9-12 月，其次高峰在10 月。每年發生豐量和各月之起伏，受晴、雨天之影響至鉅。因該成蟲多在晴朗的天氣出現。（3）大菜螟（Crocidolomia binotalis）亦全年均有出現。5-12 月為其發生盛期，高峰在9-11 月。惟每年各異，其發生除受氣象因子影響外，和白粉蝶的族群有此起彼落的現象。（4）斜紋夜盜（Spodoptera litura）亦全年出現，6-12 月為其發生盛期，高峰在11 或12 月。其發生情形和大菜螟頗相類似。（5）菜心螟（Hellula undalis）之發生盛期在4-9 月，無明顯高舉，1-3 月幾無發生。（6）擬尺蠖（Trichoplusia ni）於3-9 月為其發生盛期，因密度低無明顯高峰。（7）黃條葉蚤（Phyllotreta striolata）發生盛期因年而異，但以5-12 月之蟲數較1-4 為高。（8）偽菜蚜（Lipaphis erysimi）每年9 月至次年2 月為其發生盛期，高峰期受8 月降雨量多寡之影響，而出現在9、10 或次年1 月。（9）桃蚜（Myzus persicae）發生盛期在1-4 月，由前一年8 月降雨量多寡，可推測次年1-3 月桃蚜高峰期發生之遲早。 Seasonal occurrence of nine species of insect pests on cabbage was investigated in southern Taiwan during 1982 to 1984. Plutella zylostella was abundant from December to March of the next year with population peaks in February. Artogeia rapae crucivora appeared from March to May with a peak in April or March; and from September to December with a peak in October. Crocidolomia binotalis occurred almost year round but was numerous from May to December with a peak in November. Spodoptera litura also occurred in the warmer months from September to December with peaks in November or December. Hellula undalis occurred from April to October. Its population is very low. Trichoplusia ni occurred very often in the warmer months with no peak period. The looper was extremely low as compared to other species. Phyllotreta striolata occurred almost year round. Lipaphis erysimi occurred periodically during the dry seasons. Its population was drastically affected by rainfall. Myzus persicae also occurred periodically as that of the turnip aphid, but appeared several months later and almost constantly occurred in November during the three years. The population abundance was also greatly influenced by the rainfall during the spring.