Now is the time to be diligent in checking for cotton pests. We have been monitoring spider mites and sliverleaf whiteflies (SLWF’s) for weeks now in Worth County cotton. Recently, both of these pests have increased enough to treat in some area fields. Also, this week we have noticed target spot in a few fields. Weather conditions have been favorable for target spot, and we should check especially in fields with rank plant growth/closed plant canopies with longer leaf wetness periods.
The above pictures show spider mite feeding in cotton and target spot in cotton. As spider mites feed more, the symptoms seen on the top of the leaf may appear more reddish or purplish; at first glance it may look similar to nutrient deficiency of some type, but take a closer look for spider mites. Target spot will start in the lower canopy of the plant and move upward – be sure to check lower leaves for early disease incidence.
In the last two weeks, we have seen an increase in the silverleaf whitefly population in portions of Worth County. More fields are hitting the threshold for treatment; while some areas of the county do not have SLWF issues at this time, it will not hurt to scout on a regular basis for this pest. UGA has a couple of great resources on silverleaf whiteflies that can help in scouting and managing.
Managing Silverleaf Whiteflies in Cotton – this publication lists guidelines and insecticides that are labeled for use. (See it below)
If you have questions about these pests or need assistance, contact your local county agent.