Paper wasp Polistes jadwigae

The paper wasp Polistes jadwigae belongs to the order Hymenoptera, family Vespidae. As a social insect, it has become an increasingly significant pest in orchards and vineyards, particularly in warmer climates where the activity period of these wasps overlaps with fruit maturation.

This species primarily damages high-sugar fruit crops. The most affected cultures include grapes, peaches, pears, apples, and plums. The wasps chew through the skin of the fruit to feed on the pulp, which destroys the marketability of the produce and invites secondary infections such as fungal rot and fermentation.

The biology of the species is typical for paper wasps. In the spring, a queen that has overwintered establishes a new nest, constructing cells from masticated plant fibers. The life cycle progresses through egg, larva, pupa, and adult stages. The colony grows throughout the summer, reaching peak population density just as fruit begins to ripen.

The damage caused by these wasps is distinct, characterized by deep cavities or irregular holes in the fruit epidermis. The economic impact is two-fold: direct loss of harvest and the attraction of other secondary pests or pathogens that quickly spread decay throughout the clusters or branches.

Control measures require an integrated approach to management. Recommended strategies include:

• Deploying bait stations and traps containing attractants.
• Strict sanitation by removing fallen or damaged fruit from the field.
• Using protective netting to cover grape clusters or individual branches.
• Locating and removing wasp nests in the vicinity of the garden before peak harvest season.