(27(1):47-52)BIONOMICS OBSERVATION AND CONTROL OF MANGO BROWN LEAFHOPPER(Idiocerus niveosparsus Leth.)

檬果褐浮塵子(Idiocerus niveosparsus Leth.)為檬果花期之主要害蟲，成蟲產卵於幼葉葉脈中肋或花梗組織內，使該組織表面產生縱裂，形成機械損傷，亦為病原菌浸入之門戶。若蟲、成蟲皆在花穗或嫩葉上刺吸汁液，發生嚴重時招致花穗枯萎、花蕾脫落，影響結果甚大。其分泌物會誘發煤病，阻礙光合作用，至後期尚可污染果實外觀。 本蟲為漸進變態，若蟲脫皮四次而達成蟲。全年均有發生，並無嚴格越冬現象，在檬果生育期中有嫩葉即可產卵繁殖，無嫩葉時，僅可見成蟲。其發生密度由2月逐漸增加，至3月中旬達最高峰，4月中旬便逐漸減少。 以Tamaron等十種殺蟲劑進行防治比較試驗，各殺蟲劑濃度均採用0.05%，在田間重複試驗二次結果，以Tamaron、Sevin及Lannate等三種殺蟲劑防治效果最佳。 The mango brown leafhopper (Idiocerus niveosparsus Leth.) is the most serious pest of the mango trees. The adults of the hopper lay eggs within the midribes of young leayes, stalklets and florets, causing a physical injury. The juice of the florescense is sucked by a large number of nymphs and adults, and result in withering of flowers. The secretion, known as honeydew, excreted by these insects, covers the florescense, shoots and leaves, the sooty molds develop on it in moist weather, but dries into dark grey incrustation, which not only interfere with photosynthetic function of the leaves but also result in nonsetting of fruits. The leaf hoppers belong to the gradual metamorphosis, which molt 4 times with a total of 4 nymphal instars to adult. No hibernation was found in south part of Taiwan. The population density increases coincide with the flushes of flower of mango from Jan uary to the peak between March and April, and decreases gradually after April. Ten insecticides were tested in field against the hoppers in two different orchards with different level of population. There were three trees in one block, replicated 4 times with complete randomized designed. Four application were applied at ten days intervals. Results were investigated ten days after the last application by counting the ecdysis of the nymph remained on the leaves. Ten leaves were randomized taken in each tree. Tamaron, Sevin and Lannate were found to be the promising insecticides and the same results were got in both fields as tested in this trial