48 INSECTS AFFECTING VEGETATION 



body also becomes almost equally dark. The anterior segments are 

 much swollen, covering up and concealing the head and thoracic legs. 



As soon as the larva emerges from the egg it begins feeding on 

 the upper surface of the leaf, eating out small holes or patches about 

 the size of a pinhead or smaller, but never eating entirely through the 

 leaf. The larvae feed almost invariably on the upper side of the 

 leaves and the minute eaten spots which they make at the start rap- 

 idly increase in size until much of it, but not the entire surface of the 

 leaf, is denuded, leaving merely a network of veins, or a leaf skeleton, 

 held together by a nearly intact lower epidermis. 



The best means of destroying the slug-worm is to spray the 

 plants with an arsenical wash or with a simple soap solution. The 

 larvae are delicate and easily killed, and as they eat almost exclu- 

 sively on the upper surface of the leaf where the poison can be most 

 easily placed, they get the greatest amount of it and are the easiest of 

 all larvae to be thus exterminated. The plants may be sprayed with 

 Paris green or other arsenical wash at the rate of 1 pound of the 

 poison, mixed with an equal amount of lime, to 250 gallons of water. 

 The soap wash to be effective must be applied at a strength of one- 

 half pound of soap to a gallon of water, first dissolving the soap, 

 preferably whale oil, by boiling in a small quantity of water. (Cir. 

 26 U. S. D. A. B. E.) 



The Codling Moth on Pears. The pear crop of California suf- 

 fers much from injury by the codling moth, and in view of the com- 

 mercial importance of this crop, the losses represent in the aggregate 

 a large item. The injury is especially important on green fruit des- 

 tined for shipment to eastern markets, but even in the case of drying 

 stock there is without doubt an important deterioration in quality. 

 For description of the insect and its life history see the Codling Moth 

 under Apple Insects. 



There are practically two full broods of larvae in the pear-grow- 

 ing districts of the interior counties of California. Comparatively 

 few of the first-brood larvae go over the winter. The number of first- 

 brood larvae being relatively small, the injury is not so noticeable, 

 and many growers overlook the importance of destroying this brood 

 of worms to prevent the greater damage by the more important sec- 

 ond-brood Iarv33, which begin to enter the fruit just prior to the first 

 picking. The first-brood larvae begin entering the fruit about a 

 month after most of the petals have fallen, though this time may 

 vary somewhat with the season. All spraying for the first brood 

 should be done within three to four weeks after the blossoms are oflB 

 the trees. 



Two, and preferably three, treatments are advised, using ar- 

 senate of lead at the rate of 4 pounds to each 100 gallons of water. 

 The first application should be made as soon as most of the petals 

 have fallen, and especial pains should be taken as nearly as possible 

 to fill each calyx cup with the poison. The trees should be drenched. 

 The second treatment should come three to five weeks after the fall- 

 ing of the petals. The third application should be given nine or ten 

 weeks after the falling of the blossoms, or about two weeks before 



