Plum seed wasp

The plum seed wasp (Eurytoma schreineri) is a significant insect pest belonging to the order Hymenoptera and the family Eurytomidae. It is a notorious specialist that targets stone fruits, causing severe economic damage in agricultural orchards.

This pest primarily affects trees within the Prunus genus, most notably plums, damsons, and mirabelle plums. The larvae feed internally within the developing pit, effectively hollowing out the kernel and destroying the seed, which prevents the fruit from developing properly.

The biology of Eurytoma schreineri involves a univoltine life cycle, meaning it completes one generation per year. Larvae overwinter in a state of diapause inside the hardened pits of fallen or mummified fruits. As temperatures rise in spring, they pupate and emerge as adults just as the trees begin to set fruit.

The damage caused by this insect is insidious because it remains hidden inside the pit for the duration of the larval stage. Growers often only notice an infestation during the pre-harvest period when affected fruits begin to drop prematurely or show signs of premature color change and shriveling.

Integrated pest management strategies to control the plum seed wasp include:

• Strict sanitation practices, such as removing and destroying all fallen fruit (mummies).
• Tilling the soil under the canopy in autumn to bury and kill overwintering pupae.
• Applying targeted insecticides during the short window of adult emergence before egg-laying occurs.
• Monitoring adult flight using sticky traps to determine the optimal timing for intervention.