58 INSECTS AFFECTING VEGETATION 



tree ; and if the worms are small their discovery is almost or quite im- 

 possible. A single going-over of the trees is thus only partially effec- 

 tive, and many orchardists have found that three times during the 

 winter will not exhaust the supply, even though it is quite certain 

 that no moths were flying during the intervals. The rush of other 

 work usually prevents a summer digging-out of the worms, though 

 it would seem that just as good or better results might follow from 

 work at that season. (Bui. 143, Cal. Exp. Sta.) 



The Peach and Plum Slug. The adult sawflies are very active 

 little insects. If one is observed on a leaf it will be seen to run back 

 and forth across the leaf on the upper side, apparently peering over 

 the edge, occasionally stopping for a moment at one of the nectaries 

 at the base of the leaf and sipping the nectar. This sort of food 

 seems to constitute their diet, as, in addition to visiting the peach- 

 leaf nectaries, they were also observed visiting near-by cotton plants 

 for nectar and honeydew, and one was seen on Japanese quince. 



The first damage by the larva consists in very small pinholes 

 eaten into the leaf from the underside, all of the tissue being removed 

 except the upper epidermis. As the larva grows and its jaws become 

 stronger the size of the eaten patches increases until they become 

 large blotches. The upper epidermis is, however, never eaten. So 

 serious a menace is this insect to the peach and plum trees that, in 

 a favorable season, the trees are completely defoliated in August. 



Lack of time prevented the writer from making any tests of 

 remedies. Without doubt, however, an arsenical spray, such as 

 arsenate of lead, would very effectively destroy these insects, and this 

 poison is advised when the insects occur in sufficient numbers to war- 

 rant treatment. The rapid increase in the spraying of peaches and 

 plums with arsenate of lead in self-boiled lime-sulphur wash for the 

 control of the plum curculio and fungous diseases of the fruit will 

 unquestionably result in keeping the peach and plum slugs well re- 

 duced in orchards. Its occurrence in injurious numbers is to be 

 looked for largely in 1 small unsprayed home orchards, and the 

 remedial measures indicated should be followed when its presence 

 in undue numbers is noted. (Bui. 97, Part V., B. of E. U. S. Dept. 

 of Agr.) [See "Apple Insects."] 



PRUNE AND APRICOT INSECTS. 



The European Fruit Lecanium. The insect heretofore gener- 

 ally known as the brown apricot scale belongs to the subfamily of 

 scale insects, the Lecaniintc, being naked but with hardened derm, 

 and differs from the San Jose scale and European pear scale in that 

 the horny covering of the full grown scale is a part of the body of the 

 insect, while in the case of the other species mentioned the body is 

 protected by a waxy covering made up from secretions and the 

 molted skins of the larvae. The adult female of the European fruit 

 Lecanium is about one-eighth to three-sixteenths of an inch long, 

 three-thirty-seconds to one-eighth of an inch wide, and about one- 

 eighth of an inch high, yellowish in color, marked with black. The 

 older scales are shiny, oval, convex, and often covered with a mealy 

 pruinose deposit. 



