Megastigmus wachtli

Systematic position: Megastigmus wachtli is a member of the order Hymenoptera and the family Torymidae. This tiny parasitic wasp is known for its highly specialized biology, primarily focusing on the reproductive organs of host plants.

Host plants: The pest primarily targets the seeds of various species within the genus Cupressus (cypress). By living and feeding inside the seeds, it causes significant economic losses in seed orchards and nurseries where the production of viable seeds is critical for propagation.

Biology and life cycle: The female wasp uses her ovipositor to insert eggs into the developing seeds of the host tree. Once hatched, the larva feeds on the internal tissues, consuming the endosperm and embryo. The entire larval and pupal stages occur within the seed, which protects the insect from external environmental factors and many standard contact pesticides.

Nature of damage and harm: Infested seeds often show no outward signs of damage, making detection difficult without cutting the seed open.

• Destruction of the seed embryo.
• Severe reduction in seed germination rates.
• Economic loss for commercial forestry and nursery operations.

Control measures: Controlling Megastigmus wachtli requires a proactive strategy. Monitoring the emergence period of adults is essential for timing insecticide applications. Sanitation measures, such as the prompt removal and destruction of infested cones before adult wasps emerge, are highly recommended to reduce the overall population in the area.