'98 THE FRUIT GROWERS GUIDE. 



proved effective, probably from their being applied too late, the fungus naving gained 

 access to the. internal tissue. It is recommended to spray the trees before tho fruit 

 is half grown, with Bordeaux mixture, first ascertaining a safe strength at which to 

 apply it, removing and burning the affected fruits, as the disease is almost certain to 

 re-appear where the infected fruits are left. 



Enemies. Though the plum is infested by many insects they are not particularly 

 hurtful, except in peculiar climatic conditions and seasons. 



Aphides. Yarious species of green flies infest the growing points and young leaves 

 of plum trees, causing the tips of the twigs to become fleshy, wrinkled and distorted, 

 large colonies of the insects living on the under-sides of the leaves. Aphis pruni is one 

 of the most destructive, and A. (Myzus) persicoe sometimes cause considerable distortion 

 of the young growths and clog the foliage and fruit with their secretions. The Hop 

 Aphis (Phorodon humuli, var. Mahaleb) also infests plum and damson trees in the spring 

 as late as May and June and returns to them in the autumn for egg-laying on the 

 terminal twigs, from which the parthenogenetic generations are produced on the plum in 

 the spring and early summer. The life history of aphides is given, with means for their 

 destruction, on pages 257 262, Yol. I. As a preventive it is recommended to spray 

 the trees in the autumn with the petroleum mixture described on page 261 , Vol. I. Some 

 growers have found dusting the trees with quicklime in the winter, as advised for the 

 destruction of lichen and moss, to act beneficially against the recurrence of aphid attacks. 

 The caustic soda and potash solution named on the same page (251, Vol. I.) has been 

 found very effectual as a preventive of insect infections. 



Caterpillars. The larvae of a number of moths feed on the young growths, foliage 

 and tender fruit of the plum, especially those of the March, Mottled Umber and Winter 

 Moths. These are fully treated on pages 283 297, Yol. I. Paris-green mixture, same 

 volume, page 293, has been found an effectual remedy. 



Mites. Two or three forms of mite galls are produced on the leaves of the plum. 

 The most noticeable are .the irregular patches of closely-set hairs, white at first, but 

 turning rusty on the lower surface of the leaf; there soon appear on the upper surface 

 little club-shaped galls about the size of hempseed, first pale green, then red, later brown, 

 and inside these live the mites (Phytoptus pruni). The mites also attack the leaves near 

 the margins, causing them to thicken, crippling their development. The greatest 

 mischief is uone to the young shoots by the small galls produced in the bark, which 

 singularly do not induce gum, but a dry gangrene, and the growth suffers in conse- 



