ABSTRACT
<p><b>OBJECTIVE</b>To study the biological characteristics of Dorysthenes hydropicus in the farm of Cirtus grandis, and offer scientific evidence for prevention and controlling of D. hydropicus.</p><p><b>METHOD</b>Indoor-rearing and light trap were applied to study the biological characteristics, development course and harmful effect of D. hydropicus.</p><p><b>RESULT</b>D. hydropicus reproduces one generation in 1-2 year in Guangdong province, and overwinters in the form of larvae. Its imago comes out of the earth mainly in late May after mature. The body length has great individual diversity normally ranged from 25-60 cm, It also shows strong phototaxy. One lamp can trap more than 2 000 of them per night. Female imago has a large egg load with the maximum amount of 543. The eggs hatching is in depth of 1-3 cm soil. The dominant hatching period of egg is from late June to early July, and hatchability is over 85%. The living space of larva ranges from 15-60 cm in soil. D. hydropicus has caused serious harm and lead to thousands of Cirtus grandis trees death every year.</p><p><b>CONCLUSION</b>Dorysthenes hydropicus showed serious threat to the growth of Cirtus grandis and should be prevented and controlled.</p>