Hawthorn sawfly

Systematic position. The hawthorn sawfly (Micronematus monogyniae) belongs to the order Hymenoptera, family Tenthredinidae. It is a specialized pest known for its specific host plant preference and distinct lifecycle patterns within temperate ecosystems.

Host plants. The primary host for this species is the hawthorn (Crataegus). The pest frequently infests hawthorn plants in landscaping, hedges, and nurseries, significantly impacting the aesthetic value and overall health of these shrubs.

Biology and lifecycle. Adults emerge during the spring as the host plant breaks dormancy. Females oviposit directly into the leaf tissue. The larvae, or false caterpillars, feed voraciously on the foliage throughout the active growing season before descending to the soil to pupate and overwinter.

Nature of damage and harmfulness. Larvae skeletonize the leaves, consuming the leaf tissue between veins. In cases of high infestation, the shrub may suffer from severe defoliation, leading to reduced photosynthesis, stunted growth, and a marked decline in the plant's resistance to other environmental stressors.

Control measures. Integrated pest management (IPM) is essential for effective control. Cultural practices, such as cultivating the soil beneath the plants in autumn, can disrupt the pupation process. Chemical intervention using systemic insecticides should be timed to coincide with the early larval stage for maximum efficacy.

• Regular inspection of the foliage during late spring.
• Removal and destruction of heavily infested leaves.
• Encouraging predatory birds and insects in the garden environment.
• Application of selective biorational insecticides when necessary.