154 Acarology 



The mites spend the winter within the terminal buds, the population 

 varying from ten to several hundred per bud, with about 10 per cent 

 of the buds infested. Reproduction takes place throughout the winter. 

 In the spring when the leaf buds break open the mites infest both sur- 

 faces of the leaves. The population reaches its peak in June and July 

 Eggs are laid indiscriminately on upper and lower leaf surfaces of 

 young, tender leaves, but the mites are usually found only on the lower 

 surfaces of the mature leaves, probably because the lower surface is 

 more succulent and is shaded from the sun. In cases of extremely 

 heavy infestation the mites may be found on the dorsal leaf surface. 

 First-crop figs are infested within two weeks after the fruit buds have 

 pushed out into figs. About 90 per cent of this crop is infested. Second- 

 crop figs are infested about eight days after being formed and nearly 

 all the second crop is infested by the first of July. However, as the fig 

 ripens and the eye scales loosen, the predaceous mites and thrips take 

 their toll until in a ripe fig only a few mites are to be found. These 

 mites which have found their way into the terminal buds throughout 

 the summer carry over the population during the winter. As high as 

 50 per cent of the buds examined during the summer have been in- 

 fested. 



The following account of the importance of the eriophyids has been 

 taken from Keifer 1946. 



The Eriophyid mites, variously known as gall mites, blister mites, rust 

 mites, and bud mites, are the smallest animals bearing an exterior skeleton 

 with which the agriculturist has to contend. They deform and russet leaves 

 and fruit, blast buds, and if uncontrolled will frequently put their host 

 plant out of production. 



Eriophyids exhibit a very intimate mite-host relationship, characterized 

 by considerable host specificity. Gall formation of one kind or another is 

 another aspect of this intimacy, but the majority depend on natural forma- 

 tions on their hosts and cause no discernible injury. They remain in loca- 

 tions where feeding and breeding can take place whenever temperature 

 permits, with few exceptions. The exceptions are specialized aestivating 

 forms which spend their quiescent period in dry bark crevices. 



In general there are two types of Eriophyids; the worm-like soft kinds 

 that are gall mites or bud mites, and which do all their feeding and breed- 

 ing under cover, and the rust mites, which are broader and chunkier, often 

 rather flat, which have heavy back plates to protect them against the action 

 of light and desiccation, and which feed and breed more or less on open- 

 leaf surfaces. This latter type, with few exceptions, constitutes the rust 

 mites, or leaf vagrants. 



