Peach Pests II: Insects and Mites 

 That Feed on Foliage and Wood 



Karen I. Hauschild 



University of Massachusetts Cooperative Extension System 



In "Peach Pests I" [Fruit Notes 57(2):14-16], 

 I discussed insects that feed on peach fruit. In 

 this article, I will focus on two groups of pests- 

 insects and mites that feed on peach foliage and 

 insects that burrow into and feed on peach 

 shoots or wood. 



Leaf-feeding insects (primarily aphids) and 

 mites only are occasional pests in peach or- 

 chards; however, they may cause serious injury 

 in isolated trees or blocks. Aphids may need to be 

 controlled when populations become high 

 enough to cause leaf curl or when disease trans- 

 mission is a consideration. Mites, especially in 

 hot, dry weather, can build up quickly and 

 reduce the photosynthetic ability of foliage. 



Three shoot- and wood-feeding insects cause 

 problems in peach orchards. First generation 

 Oriental fruit moth larvae bore into and feed on 

 young peach shoots causing their death. Larvae 

 of the peach tree borer and the lesser peach tree 

 borer tunnel into peach wood, resulting in dam- 

 age that often is invaded by canker diseases. 

 Additionally, heavy borer infestations can 

 weaken limbs or trunks and lead to breakage 

 and tree loss. 



Below is a brief description of each of these 

 pests, the damage each causes, and basic infor- 

 mation on non-chemical control. 



Green Peach Aphid 



The most prevalent aphid found on peaches 

 is the green peach aphid (Myzus persicae). This 

 species occurs worldwide and has a diverse host 

 range. Green peach aphids are very small, about 

 1/12 inch long. Wingless adults range in color 

 from pinkish-red in early spring and fall to 

 yellowish-green with a darker head during the 

 summer. Winged adults have a darker head and 

 thorax with a blotched yellowish abdomen. 



Young aphids (nymphs) resemble winged adults 

 but are smaller. 



In New England, green peach aphids over- 

 winter as shiny, black oval-shaped eggs on twigs 

 or bark. These eggs hatch about the same time 

 as leaves appear on peach trees. Aphids have 

 sucking mouth parts, and first generation 

 nymphs feed on unfolding leaves or flower buds. 

 These nymphs develop into wingless females 

 that bear live young, resulting in rapid build-up 

 of populations. Heavy feeding by nymphs and 

 adults can result in leaf curl, stunted growth, 

 and reduced fruit set. Several generations of 

 green peach aphids occur in a season. In late 

 spring, however, adults grow wings and move to 

 other crops, returning to peaches in late fall. 

 Nymphs produced in the fall mature, mate, and 

 lay overwintering eggs. 



If green peach aphid populations are high, 

 oil should be applied the following spring to 

 prevent hatching of overwintering eggs. In gen- 

 eral, insecticides applied for controlling other 

 peach pests will control the green peach aphid. 



Two-spotted Spider Mite 



The two spotted spider mite (Tetrannychus 

 urticae) feeds on ground cover plants in peach 

 orchards, moving to trees when ground cover 

 plants have dried due to hot weather or when the 

 ground cover is tilled or treated with herbicide. 

 The two-spotted spider mite also can become 

 troublesome when its predator, Amblyseius 

 fallacis, is killed by non-selective pesticides. 



Mites are closely related to insects, but have 

 four pairs of legs rather than three pairs. They 

 have sucking mouthparts. Adult females are 

 yellow to green with two dark patches on their 

 abdomens. They are very tiny, about 1/60 of an 

 inch long, and often can only be detected by the 



12 



Fruit Notes, Summer, 1992 



