Pip Fruits: Pears 105 



3. INSECT PESTS AND DISEASES 



Slug'worm of Pear and Cherry (Eriocampa limadna). The repulsive 

 slug-like larvae are frequently seen on the foliage of Pear and Cherry. 

 They are bottle green in colour and covered with a slimy matter above; 

 beneath they are paler, and the anterior region of the body is swollen, 

 the head being more or less sunk into it. They have sTx ^jointed legs 

 in front and seven pairs of sucker feet, and when mature change to 

 dry-skinned yellowish larvae. Their final stage reaches | in. in length. 

 The Slugworms feed upon the upper side of the leaves, but leave the 

 under epidermis intact, thus skeletonizing the foliage. When mature, the 

 Iarva3 fall to the ground and pupate in earthen cocoons. 



The female Sawfly is black and about -?> in. across the wings; the first 

 larvae appear early in June. There may be three broods, and larvae have 

 been found as late as the end of October. The winter is passed in the soil 

 in the larval stage in a cocoon of silk and earth. When they occur in 

 numbers early in the season they do most harm, but even when late they 

 may destroy so much foliage that the ripening of the wood is checked. 



TREATMENT. Treatment is best carried out by spraying the trees with 

 arsenate of lead. Dusting with fine lime has also met with success. In 

 gardens the surface soil may be removed to a depth of 3 in., and burnt, 

 in winter. 



The Pear-leaf Blister Moth (Cemiostoma scitella). The larvae of this 

 small moth form circular brown blisters on Pear and^ sometimes Apple 

 leaves. The moth appears at the end of April and May, and again in July 

 and August. The moth has leaden-grey forewings with a brown streak 

 running from the costa obliquely across the wing; also two white streaks 

 run from the costa nearer the tip separated by a coppery band; beneath 

 these a black spot with a violet pupil, fringe dingy with four dark radiating 

 lines. Wing expanse in. 



The larvae, after mining the leaves, crawl out and spin a white cocoon 

 in crevices on the tree and in the soil, in which they pupate. 



Pear Midge (Diplosis pyrivora). This small fly, which belongs to the 

 family Cecidomyiadae, causes very great loss by its maggots destroying the 

 young pears. Although it has been known for many years it has increased 

 enormously of late, and in some parts of Britain the greater part of the 

 crop is destroyed by it. 



The damage is done by the small white maggots feeding inside the 

 young pears. The infested fruitlets are very marked, they become abnor- 

 mally swollen and deformed and make rapid growth compared with sound 

 fruitlets. The infested fruitlets (known as "bottlers" in the trade) are 

 found to be black inside when cut open and to contain as many as fifty 

 maggots, which when mature reach -f in. long (fig. 359). 



The adult fly appears when the Pear blossom just shows the " white cap 

 stage". The female is only ^ in. long, the male T V in.; the latter is a dark 



