全球氣候變遷對台灣地區蟲害發生影響及因應對策

Abstract

影響害蟲族群與為害之環境因子可分為非生物因子與生物因子兩大項，兩者問之相互作用相當複雜，其中任何一因素的改變將可直接或間接地影響到一種害蟲在區域間的族群密度。全球氣候變遷導致地球表面溫暖化可直接影響害蟲之分佈、存活與族群之成長速率，同樣亦可導致作物之發育及其耕種及管理制度之演變，而影響害蟲族群之發生豐度及其為害。在全球氣候變遷下，可使台灣氣候型態更接近熱帶地區，害蟲及其天敵種類之歧異度將更形增加。冬季增加溫度減少降雨量將更有利於害蟲之越冬，增加冬作及春作害蟲之族群密度及為害損失；夏季溫度及降雨量之增高則更不利於害蟲之繁殖，可抑制其為害。由於害蟲之發生豐度受寄主作物之品種、栽培制度及管理方式等之演變影響至大，該等演變導致蟲害之損失，可能較全球氣候變遷之直接影響為大。一般而言，溫度增加，將可增加昆蟲種類的歧異度及發生世代的重疊，較難使用藥劑適時防治，宜發展以增加害蟲環境阻力，如栽植抗蟲品種、增強田間管理，生物與物理防治等非農藥防治方法為主體之綜合管理策略，抑制害蟲族群於經濟危害基準之下，則藥劑使用頻度將可大幅減少，使作物環境更有利於自然潛在天敵族群的增長而發揮其抑制各種害蟲功效。此一防蟲策略將可有效地因應地球表面暖化及社會之需求。 Insect populations are affected by abiotic and biotic environment factors. Global warming will affect the insect distribution, composition of insect foana and the rate of insect population development directly. While the insect population abundance and its damage will be depended on the changes of cultivation and management patterns of crops responding to the weather conditions and social needs. Global climate changes may convert weather in Taiwan from subtropic into tropic conditions, thus providing more favorable situation for the multiplication of arthropods, and increasing species diversity and complexity in the ecosystem. If the weather condition is going to change as predicted, a warmer and drier winter may make conditions more favorable for insects to cause more severe damage in winter and spring crop, while higher temperature and rainfall in summer will hamper the population development of insect pests. However, the total losses of crop caused by insect pests due to the changes of climate directly may be not so much as compared to those due to the changes of varieties, cultural system and management of crops. Management of insect pests in the situation of diverse species and overlapping generations by using biotic measures, such as host plant resistance, biological and cultural measures are more reliable than by insecticidal applications. When successful control of the key pests is achieved through the use of control tactics other than insecticides, opportunity for the control of various potential insect pests by natural enemies will be increased. This control strategy is not only applicable for meeting the situations of global climate changes but also suitable for social demands in Taiwan.