Symptoms are different depending on which crop is affected. On roses the flower blossoms are affected, causing large irregular shaped holes in the flower petals. On fruit trees, especially grapes leaves are fed on, eventually skeletonizing them. Also the fruit can be damaged, being partly peeled and gouged in irregular shallow patches.
The damage is caused by the adult chafer of Macrodactylus subspinosus. They are pale and slender green colored beetles with a darker head and long legs, ca. 12 mm long. The female bug lays her eggs just below the soil surface in sandy, well-drained soils with grass. Wetted soils are more preferred for laying eggs. Larvae overwinter as grubs in the soil and feed on grass roots. It affects roses, stone fruit trees, e.g. grapes, apples, cherries, peaches, pears and plums and prefers sandy soil.
Drench the soil with a parasitic nematode to kill the larvae. Pyrethrin is recommended if infestation levels are severe.
Always consider an integrated approach with preventive measures together with biological treatments if available. Apply malathion 50% EC at 400 ml in 600-800 l of water/acre on your vineyard. Other pesticides are recommended, containing acephate, chlorpyrifos, bifenthrin, cyfluthrin or imidacloprid. Avoid spraying on flowers to not harm or kill honey bees.