Aphicide persistence on spinach and mustard greens

Area of Science:

• Agricultural Entomology
• Pest Management
• Insecticide Efficacy

Background:

• Green peach aphids (Myzus persicae) are significant pests of spinach and mustard greens.
• Understanding insecticide persistence is crucial for effective crop protection strategies.
• Limited data exists on the residual activity of specific insecticides on these leafy greens.

Purpose of the Study:

• To evaluate the persistence and efficacy of three insecticides: triazamate, dimethoate, and mevinphos.
• To compare insecticide activity on field-grown spinach and mustard greens against green peach aphids.
• To determine the residual mortality of Myzus persicae over time following insecticide application.

Main Methods:

• Laboratory bioassays were performed using treated spinach and mustard green samples.
• Green peach aphids were exposed to treated plant material at various time points post-application.
• Aphid mortality was recorded to assess insecticide persistence and efficacy.

Main Results:

• All tested insecticides initially caused similar aphid mortality on both crops.
• Mevinphos showed a rapid decline in efficacy, with significantly reduced mortality by 1 day post-treatment.
• Dimethoate demonstrated persistence for over 4 days, maintaining some level of aphicidal activity.
• Triazamate and dimethoate exhibited similar persistence on spinach.
• Triazamate showed greater aphid mortality over time compared to dimethoate on mustard greens.

Conclusions:

• Insecticide persistence varies significantly, impacting long-term pest control on spinach and mustard greens.
• Dimethoate and triazamate offer more prolonged control of green peach aphids than mevinphos.
• Crop type influences insecticide residual activity, with triazamate being more effective on mustard greens.