124 SOME SOUTH INDIAN INSECTS, ETC. [CHAP. XI. 



at the most. As soon as the dry weather sets in. when the condi- 

 tions arc unfavourable for the growing of the fungi, the scales 

 increase and spread and actually do most damage at this tin 

 year probably largely because they drain the juices of the hushes 

 just when moisture is most deficient. Endeavours to spread the 

 fungus artificially during the wet season would seem a wast 

 time, because it is able at that time to spread by itself prac- 

 tically wherever the scale is, and during the dry season the 

 conditions are unfavourable to the growth of the fungi unless 

 perhaps these were actually placed artificially in contact with 

 the scales, and in this latter case it would be less trouble to use 

 .mi insecticide and kill the scales directly. One case only has 

 been quoted, and this under as favourable conditions as are likely 

 to be found in Southern India for the control of an insect pest by a 

 lungus, and it may be seen that these conditions are not suitable or 

 comparable with those in other countries in which no really dry 

 season is experienced. And this is quite apart from the practical 

 difficulties of manufacturing cultures of such diseases on a large 

 scale, although this is a point of importance especially in the case 

 (it bacterial diseases. Experiments with a Bacterial Disease of 

 Locusts, caused by Coccobacillus acridiorum, have apparently been 

 successful in South America, but in South Africa Lounsbury's 

 experiments appear to show that this method is of comparativelj 

 little use on a held scale (Agricultural Journal of South Africa. 

 April I9I3)- 



Insect Parasites. — The use of insect parasites is, however, a 

 method which is not only useful and practical but is to some extent 

 within the reach of all cultivators. When eggmasses of pests, foi 

 example, are found affixed to leaves of CTOpS, instead of destroying 

 them forthwith, they may be removed and placed in receptacles 

 surrounded by water or oil in such a way that any caterpillars 

 which hatch out may be unable to escape, whilst any parasitic flies 

 which emerge from the eggs may be free to tl\ away to continue 

 their beneficial task of egg-destruction. Similarly, shoots or stems 

 attacked by caterpillars, or pupae, maj be placed in chattit 

 similar tight receptacles and covered over with a piece of mosquito 

 netting or moderately fine wire-gauze, so that anj moths which 

 emerge maj not escape whilst any small parasites may do so; but 

 it must be remembered that not every parasite that emerges is 

 beneficial, as some are hy perparasites or superparasites which 

 do harm and not good. Some account oJ beneficial insects and 

 parasites is given in a later chapter. 



Legislative Enactments for the control of Insect Pests aim as a 

 rule at prevention of the importation of new pests rathei than al 



