Paper wasp

The Polistes exclamans is a social wasp belonging to the order Hymenoptera and the family Vespidae. Known for constructing open-comb nests from papery pulp, these wasps are common in various agricultural landscapes. While they serve as predators to some pest caterpillars, their tendency to feed on high-sugar food sources makes them an economic concern during harvest season.

These wasps primarily damage succulent crops, including grapes, strawberries, peaches, and figs. They are particularly attracted to overripe or wounded fruit. By puncturing the skin of the produce, they feed on the internal juices, which directly compromises the quality and marketability of the affected agricultural products.

The biology of Polistes exclamans involves a queen-founded colony that expands throughout the spring and summer. As the colony grows, the demand for carbohydrates increases to support the energetic needs of the workers. This shift in nutritional focus aligns with the maturation of many fruit crops, leading to increased pressure on orchards and vineyards during the harvest period.

Damage assessment typically reveals shallow pits or deep holes in the fruit epidermis. These lesions are not merely cosmetic; they serve as entry points for secondary infections such as molds, yeasts, and bacteria. Consequently, a small initial damage caused by wasps can rapidly escalate into the decay of an entire fruit cluster or storage lot.

Integrated pest management strategies involve the early detection and removal of nascent nests in agricultural outbuildings. To protect standing crops, exclusion techniques such as fruit netting or bagging are highly recommended. While chemical control is possible, it should be used judiciously to avoid destroying beneficial pollinators and natural predators that reside in the same ecosystem.