The Biology and Control of the Sugar-cane Chafer Beetles in Tanganyika

Abstract

The first record of a Melolonthid (cockchafer) larva as a pest of sugar-cane in Tanganyika was in April 1941, when about 25 acres on the Arusha Chini (Moshi) estate of the Tanganyika Planting Company were found to be infested. Subsequently, the main swarming period of the adult beetle has been observed from the beginning of October to late November, and a minor period at the onset of the long rains in March. The identity of the pest was established in 1943 as Cochliotis melolonthoides (Gerst.), a native species fairly closely allied to the European cockchafer, Melolontha. Several other associated species of minor importance have since been identified. Field and laboratory studies have also been made by W. V. Harris, and his recommendations have enabled a certain measure of check to be kept on the intensity and spread of the damage. The writer succeeded Mr. Harris at Morogoro, and after nearly two years' study of this problem wishes to acknowledge the numerous and valuable data which have been freely drawn upon in preparing the present paper, which is an attempt to summarise the facts known about the cane beetles and the suggestions which have been made for their control. The present recommendations are made in the light of over ten years' study of methods of control of the sugar-cane beetle, Clemora smithi (An*.), in Mauritius and of two seasons' field observations on Cochliotis melolonthoides on the above-mentioned infested estate in Tanganyika. The method of chemical control by BHC-dust application in the furrow has since been tested over five years and whilst it has been shown to be essential to protect the virgin canes and to a certain extent the first ratoon, the problem of protecting the second and subsequent ratoons remains a matter for future investigation.Sugar-cane in various stages of development, both as plant cane and ratoons, begins to show serious signs of root infestation each year in July, and by September or October a seriously infested field will show patches of stunted plants with curled and yellowed leaves; the patches tend to follow the main irrigation furrows. The stools of cane can be lifted easily from the soil, their roots having been severed by the feeding of the larvae. In young plantations, the young shoots and roots are eaten and the larvae then hollow out the setts. In this way, fields which gave 45 to 80 tons per acre in virgin fields and 30 tons in ratoon cane may be reduced to single-figure yields. The infestation spreads but slowly and takes several years to attain its zenith in one field. The environmental resistance to the insect is then slowly built up in the form of insect parasites and predators, fungal and bacterial diseases and these, aided by vigorous cultural measures enable the land to be cultivated profitably once more until the beetle again builds up a population of damaging intensity. The present position is that several hundred acres are gradually being won back to cane cultivation with the beetle advancing slowly but steadily over the rest of the estate. Success i...

THE BIOLOGY OF LEPIDIOTA REULEAUXI BRENSKE (COLEOPTERA: SCARABAEIDAE), A PEST OF SUGARCANE IN PAPUA NEW GUINEA

“…Adult emergence and mating just before dusk after rainfall seems typical of melolonthines (Illingworth and Dodd 1921;Jepson 1956;Barrett 1966;Wilson 1969;Chandler and Chapman 1989). Unlike L. vogeli (Barrett 1966) and L. squamulata (Chandler and Chapman 1989), adults of L. reuleauxi do not appear to feed.…”

A two-step mechanism controls the timing of behaviour leading to emergence from soil in adult males of the scarab beetle Dasylepida ishigakiensis

“…Recent studies report intriguing behaviour in adults of this species (Arakaki et al , 2004; Fukaya et al , 2009). Adults emerge from the ground for mating at dusk, as is commonly observed for other scarab beetles (Jepson, 1956; Barrett, 1966; Wilson, 1969; Chandler & Chapman, 1989; Kuniata & Young, 1992). However, this beetle reproduces during the coldest months (February and March) of the year when the mean monthly temperature is 17–20°C.…”

On the bionomics and ecology ofHeteronychus licas(Klug) (Coleoptera, Dynastinae), a new pest of sugar-cane in Nigeria

“…Natural enemies.-The use of natural enemies in the biological control of a variety of sugar-cane pests has been adopted in different parts of the world. Indigenous parasites and predators have been encouraged, or new ones have been introduced (Jepson, 1956). During the present study, almost all the natural enemies seen attacking larval or adult stages of Heteronychus were predators.…”

“…In Tanganyika, a serious infestation of Cochliotis melolonthoides (Gerst.) was shown to reduce the virgin yield of sugar-cane from 45-50 to 15-20 tons per acre and to eliminate the ratoon crop after one or two years (Jepson, 1956). This emphasizes the seriousness with which H. licas should be regarded in Nigeria and indicates the potential magnitude of the problem that might arise.…”