嘉南地区柯氏食菌瓢虫季节性发生、取食对象、生活史及瓜类白粉病防治潜力评估

本研究调查柯氏食菌瓢虫(Illeis koebelei)在台湾南部地区之取食对象及发生生态，调查柯氏食菌瓢虫在田间栖息於11种罹白粉病植物，该植物为大波斯菊、王瓜、台湾栾树、向日葵、阿勃勒、柿子、洋香瓜、桑树、破布子、辣椒及蟾除草，其中柿子、阿勃勒与破布子因罹白粉病的期间差異可能是柯氏食菌瓢虫之主要栖息植物。调查该虫几乎周年性发生，9月在夏秋交际时开始在柿子葉片及果实上发生，11月至隔年3月底普遍出现在许多罹患白粉病植物上，4月後气温昇高數量逐渐减少，夏季白粉病不易发生之逆境下，较容易在破布子植株上发现成虫。该虫取食之白粉病菌病原有Bulbouncinula、Leveillula、Oidium、Ovulariopsis、Phyllactinia及Podosphaera等6个属。在实验室中飼养观察，成虫产成批卵。1龄幼虫灰色，体表具块狀黑斑及长刺毛；2~4龄幼虫体表颜色加深，体表具短刺毛；蛹白黄色，各体节具块狀黑斑；成虫前胸节乳白色，具兩块狀黑斑，翅鞘鲜黄色。在日温24℃与夜温20℃条件下，卵平均发育3.3天；幼虫期为10.4天；蛹期4.4天；成虫期为13.3天。4龄幼虫与成虫平均食菌速率显着大於前3龄幼虫，分别为每小时1.02及1.75立方公分。评估该虫可适合於防治有机栽培瓜類及果树作物白粉病，预估在200平方公尺之设施有机栽培园中，理想的野放成虫总只數约12,000~15,000只。

科尔沁区异色瓢虫色斑多型现象季节性发生研究

对2018和2019两年通辽市科尔沁区异色瓢虫(共计3582头)进行色斑多型现象的季节性发生研究,共发现105类色斑变型,具体为黄底型变型96类,黑底型9类,其中当地新记录色斑变型78类。从季节分布看,夏季具色斑变型49类,秋季有87类,所有变型中以十九斑变型个体数量最多。黄底型高斑类型(16—19斑)占比在夏秋两季均显著高于低斑(0—7斑)和中斑类型(8—15斑);同一类型中低斑、中斑类型在夏季占比明显较高,高斑类型则在秋季占比显著高于夏季。黄底型异色瓢虫鞘翅各斑点出现概率在秋季均高于夏季,但概率大小顺序在夏秋两季大体相同,均以斑点3出现概率最大,斑点1/2出现概率最小。

SEASONAL PERFORMANCE AFFECTING POPULATION DYNAMICS OF CITRUS RED MITE, PANONYCHUS CITRI (MCGREGOR) (ACARI: TETRANYCHIDAE), ON PEAR

The population of the citrus red mite, Panonychus citri (McGregor), does not increase on pear from spring to mid summer but thereafter increases abruptly. To elucidate this phenomenon, we compared the performance of the mites on pear leaves with that on citrus leaves, at different time throughout the pear growing season. No significant difference was detected between the oviposition rate on pear and that on citrus throughout the season. However, the survival rate of ovipositing females that had fed on pear and the hatch rate of eggs laid by those females were significantly lower than those for females that had fed on citrus, until August. However, no significant difference was observed thereafter. The results showed that the decline of the population of citrus red mite before autumn is due to the high mortality of adult females that had fed on pear leaves and the low hatch rate of the eggs produced by those females.