Insect present in many parts of the world (mainly in Africa and Asia) which causes extensive damage to Cucurbitaceae crops in Mayotte. Uniformly orange in color, it belongs to the Galerucinea subfamily.
Observed in the open field as well as under shelters.
Sensitive botanical family (s)
Cucurbits
Affected production areas :
Mayotte
Organs attacked
Leaves
Flowers
Fruits
Stems
Roots
Symptoms, damage
Symptoms :
Leaves eaten mainly by adults which feed on the blade. This is cut out, perforated more or less regularly (figure 1), the veins sometimes remaining in place and giving the leaves the appearance of lace.
The damage can be very important on young plants, older plants can be completely defoliated in the event of a strong attack.
Flowers and fruits sometimes eaten and cut.
The larvae that live in the soil can attack the roots and stems causing necrosis at the wounds. Young fruits in contact with the ground can also present galleries due to larvae (case of cucurbits creeping: squash, watermelon, zucchini, etc.).
Signs : Presence of adult insects on plants and in the crop.
Possible confusion : damage that may also be associated with defoliating caterpillars, phytophagous ladybirds, etc.
Biology
Development cycle :
3 larval stages in the soil at root level.
The metamorphosis takes place in the soil.
The duration of the cycle, larva - adult, is about 1 month.
Adults feeding on the foliage and flowers of Cucurbitaceae. They are usually over 5mm in size. They are recognized by their orange color (figures 2 and 3).
Protection
Reasoning irrigation . A high soil moisture content is a favorable factor for the development of larvae.
Produce the plants in an nursery insect-proof (instead of sowing in the open field) and check their sanitary quality before and during their introduction into the crop or shelter.