What Does the Green Peach Aphid Look Like? A Detailed Guide to Its Morphological Characteristics and Control Techniques

There are three kinds of aphids that damage peach trees, namely the “green peach aphid”, the “mealy peach aphid”, and the “peach leaf-curling aphid”. After being damaged by the green peach aphid, peach trees show curled, thickened young leaves, uneven leaf surfaces, large numbers of aphids sucking leaf sap, greatly reduced leaf function, and excretion of sticky honeydew that contaminates branches and leaves, inhibits new shoot growth, and causes leaf drop. Let us take a look below at the introduction to the morphological characteristics and control techniques of the green peach aphid.

I. Morphological Characteristics of the Green Peach Aphid

Adult: The winged viviparous female is 1.8-2.1 mm long; the head and thorax are black, the abdomen is green, yellow-green, brown, or reddish-brown, with black spots on the back; the wings are relatively long and large, the abdomen is slightly slender, and the cauda is conical; the frontal tubercles are prominent and slant inward. The wingless viviparous female is about 2.0 mm long; the body is pear-shaped, entirely green, orange-yellow, reddish-brown, etc., with great color variation and a glossy surface, and other parts are the same as the winged aphid.

Egg: Initially orange-yellow, later turning black and glossy, elongated oval, 0.5-1.2 mm long.

Nymph: Small in body, resembling the wingless viviparous female.

II. Occurrence Pattern of the Green Peach Aphid

In a normal year, about 10 generations occur. It overwinters as eggs in bud crevices and cracks in the bark, and begins to hatch and cause damage when peach trees sprout in spring. These peach aphids are all migratory aphids; around wheat harvest they fly to other hosts, and in autumn they migrate back to peach trees to cause damage. The period from peach budding to flowering is the peak hatching period, and April to May is the peak damage period of the year, when they can suck leaves dry, causing them to lose photosynthesis and die. From June to July, mating and reproduction begin, and hatching is generally completed in 20 days. These are called winged viviparous females; the aphids usually referred to are parthenogenetic viviparous aphids, which can reproduce dozens to more than a hundred nymphs at a time. By August to September the numbers decrease, and in October to November sexual aphids are produced, which after mating produce the overwintering eggs.

Specifically for each aphid species, the hatching period is: the green peach aphid hatches at the budding stage, the peach leaf-curling aphid hatches at the flowering stage, and the mealy peach aphid hatches after flowering. It is recommended to start applying pesticide when 80% of the flowers have fallen, and the earlier the better.

III. Control Techniques for the Green Peach Aphid

1. In combination with spring pruning, cut off severely damaged branches and tips and burn them in a centralized manner.

2. Protect and utilize natural enemies such as ladybugs, lacewings, hoverflies, and aphidius wasps, and use aphid-specific insecticides as much as possible.

3. Arrange tree species rationally; tobacco, cabbage, and other crops should not be planted between peach tree rows or near the orchard, so as to reduce summer breeding sites for aphids.

2. Taking advantage of the green peach aphid's attraction to yellow, hang yellow sticky traps in the peach orchard to trap and kill them. The density is generally 30 traps per 667 sq m, the size is 25 cm × 30 cm, and the hanging height is at the middle of the canopy.

3. Spray pesticide in spring before peach flowers open but after all aphid eggs have hatched and before peach leaves curl; after flowering to early summer, spray pesticide another 1-2 times according to pest conditions. When the population migrating back to peach trees in late autumn is large, pesticide can be sprayed again. Eliminate winged aphids before they outbreak massively or disperse by migration.

4. The key period is when 80% of the flowers have fallen. At this time the young peaches have not yet emerged from the shell, and a few “escapees” from the first control can be found sporadically; applying pesticide at this time can achieve twice the result with half the effort. Imidacloprid or thiamethoxam + pymetrozine + kung fu can be sprayed.