As the weather gets cooler, aphids are migrating back to the desert to harm our crops. It is important to revisit some factors that may favor aphid infestations in your crops, specifically lettuce, and take appropriate action against them.  

Nitrogen availability is one of the most important factors in the development of insect pest populations. Excessive application of nitrogen fertilizer to crops will likely increase the feeding preference and consumption rate of insect pests such as aphids, resulting in greater survival, growth, and reproduction. In some situations, high nitrogen levels in plant tissue can decrease resistance and increase susceptibility to aphids’ attacks.

Water management is also very important to consider. Excess water around plant roots can increase nitrogen uptake, which may favor an increase in the aphid population. Thus, supplying proper amounts of nitrogen and water to your crops can tremendously help with aphid management. See this link for more information on this topic.