The egg when first laid is translucent-white, later becoming yellow, slightly convex, round or slightly oval, measuring about 0.7 mm across. The full-grown larva has a length of approximately 12 mm, and is pink to almost red. The head, the prothoracic notum and the anal plate are brown. A black anal fork (anal comb), above the anal opening, is present.
The cocoon is a protective covering for the full-grown larva and pupa. It is made of silken threads and particles of the objects on which it rests. The pupa is reddish-brown. The adult has a wing span of 10-16 mm, and is dark-grey. When at rest, the wings are held in a roof-like position over the body, and the antennae are bent backwards over the wings. For exact identification, investigation of the genitalia is necessary.
Detailed morphology can be found in Balachowsky (1966).
The first signs of G. molesta infestation at the beginning of the growing season usually include clearly visible wilting, drying and brown lateral shoot tips (Il’ichev et al., 2003).
Related invasive species
- Grapholita molesta
Related Farm Practice
- Orchards
- Rest
- Growers
- Prices
- Feeding
- Identification
- Damage
G. molesta causes damage of varying importance on peaches, nectarines and apricots. The larvae of the first generation are mostly found in buds and shoots of peaches, but occasionally also on shoots of apricots, plums, almonds, cherries, apples, pears and quinces. In young trees when terminal twigs are attacked, several lateral shoots will appear below them and grow rapidly. Under severe and continued attack, the tree may become somewhat bushy. Severe attacks on the rapidly growing shoots of recently budded peaches result in crooked stems.
In harvested peaches there are two distinct types of injury. One is caused by larvae that have abandoned the twigs, feeding on, or entering into, the side of the fruit early in the season when the fruit is small. It is frequently called 'old injury'. The second type of damage is caused by entrance at the stem, called 'new injury', and occurs when the fruit is almost fully grown. This injury is caused by newly hatched larvae that go directly to the fruit. The surface indications of the presence of maggots in the fruit are frequently obscure and occasionally lacking, and only a small part of such injured fruit can be detected during grading. The loss sustained by growers from this type of injury is in reduced prices for their fruit (USDA, 1958). In France, this pattern of injury is characteristically seen on nectarines. On downy-skinned peaches, the reverse may be seen (early attacks at the stalk, later attacks at the side of the fruit). G. molesta damage also favours brown-rot infection (Monilinia spp.). Fruits of other species are also occasionally attacked in the vicinity of peach orchards.