67 



12. Plum Bark Beetle, Scolyttts rugulosus . Order Coleoptera 



13. Green Leaf Weevil, PhyUobius tnaculicomis „ „ 



14. Brown Leaf Weevil, PhyUobius oblongus . „ 



15. Red-legged Weevil, Otiorhynchus tenebricosus „ „ 



16. Oblong Leaf Weevil, PhyUobius oblongus. 



These insects can generally be easily dealt with by spraying the tree 

 when the larvse are seen with 4-6 lb. of lead arseniate to 100 gallons 

 of water, or shaking the trees over tarred paper in the cases of the 

 Coleoptera. 



INSECTS ATTACKING THE PLUM TREE. 

 " Sucking Insects." 



I. The Plum Aphis, Aphis pruni. Order Rhynchota. 



This is a leaf-curling aphis, and attacks all kinds of plums, and is 

 known as a bad pest all over England. 



The eggs are laid on the trees in winter, and the larvae emerge from 

 them in early spring, being then of a dark-green colour. 



They grow rapidly, and the majority develop into apterous, 

 viviparous females, being of a deep green or brown colour. 



They have light-brown antennae, dark-brown comides, and three 

 faint green stripes on the abdomen. 



These females produce young, which develop into viviparous 

 females. About June, rudimentary wings are formed, and the pupal 

 stage commences. The pupae are shiny green in colour, with brown- 

 edged wing cases, and very dark cornicles. About the middle of 

 June the pupal stage is almost over, and from these pupae you get 

 winged viviparous females, which leave the plum, returning to it in 

 the autumn, when they produce young which in time give rise to 

 winged males and wingless oviparous females, and many more females 

 are produced than msdes. 



In October there can be seen nxunerous bright, shiny, blackish eggs. 



In spring the leaves become quite covered with the aphides and 

 their excreta, and by their puncturing apparatus the leaves curl up, 

 making it very hard for spraying. 



Insecticides. — Spra5mig in spring before the leaves ciurl up with 

 paraffin emulsion : soft soap 3 lb., paraffin 22 oz., water 9 gallons. 



The soap is dissolved in the water, and the paraffin is chmned 

 gradually and thoroughly with it, and spray with this only before the 

 leaves have curled, as it would not get to the aphides once they have 

 succeeded in curling the leaf. 



2. The Mealy Plum Aphis, Hyalopterus pruni. 

 Order Rhynchota. 



This aphis is different from the last, as it does not curl the leaves, 

 but collects beneath them in dense, mealy masses. 



The insect is of a pale-green colour, with a covering of mealy 

 secretion. 



