May Q&A: From fire ants to cucumbers and tomatoes

There are many things going on in the garden this time of year, so let’s hit on several issues by doing a question and answer session. 

Q: I have fire ants in my yard, what can I do about them?

A: Fire ants are very distinctive yet strangely are often misidentified so the first step is to make sure what you are dealing with are truly fire ants.  Fire ants make much larger mounds than other insects; they can be as large as 2 feet wide and 18 inches tall. In clay soils the mounds are typically dome shaped but are more irregularly shaped in sandy soils.  The ants themselves range in color from red to dark brown. Treating the mounds can be done either through application of a liquid insecticide or a bait. Liquid insecticides work quickly but rarely kill all ants in a mound, so repeat applications will be necessary.  Baits take longer to work, but will ultimately kill a larger amount of the ants present in the mound and are easier to apply than liquids.  If the fire ants are in a high traffic area where a quick fix is needed, liquid sprays (Sevin, Orthene, pyrethroids) are best, just know that a second and possibly third treatment will be required.  Otherwise baiting with Amdro is probably the best option.

Q: I have small yellow insects crawling on my cucumber plants. Are these harmful and if so, how can I control them?

A: Chances are, you are seeing cucumber beetles.  They look somewhat like ladybugs but with longer bodies and they are yellow or light orange rather than red.  They will have either black spots or stripes on their back.  These insects chew on the young stems and leaves of cucumbers, cantaloupe, squash, pumpkins, watermelons, beans and peas, causing poor growth and yield.  They may also occasionally carry diseases that they transmit to the plants through feeding.  Plowing the garden a few weeks early and planting a few weeks later than normal at high seeding rates may help control them.  You can also spray esfenvalerate (Ortho Bug-B-Gon Insect Killer) on many of the vegetables mentioned.  Check the label for specific directions.

Q: Every year my tomatoes get large, black spots on them.  What can I do about this?

A: Tomato blossom end rot is one of the most common things I am asked about.  It is a nutritional disorder of tomatoes resulting from a lack of calcium in the soil, which can sometimes be worsened when there is uneven moisture in the soil (alternating periods of very wet to very dry).  Normally I recommend gardeners who grow tomatoes add a handful of lime to the planting hole when setting out their tomatoes, in addition to the regular lime and fertilizer that they may give their garden as a whole.  Because lime is slow acting, it's likely a bit late to get much response from adding lime to tomatoes now Instead, you can consider adding a small amount of gypsum (usually found in the fertilizer section of the garden store), Epsom salt or crushed eggshells.  Of course, it is always helpful to take a soil sample of the area to find out the exact amount of fertilizer and lime needed prior to planting each year. 

The Roanoke Valley Farmers Market is open from 8 a.m. to 2 p.m., Wednesdays and Saturdays. Strawberries, asparagus, many greens, onions, potatoes, and some hydroponically grown greenhouse vegetables are available, as well as baked goods, crafts and rain barrels. 

Matthew Stevens is the horticulture extension agent for Halifax County Cooperative Extension.  If you have any questions about this article or other aspects of your home gardening, please contact Matthew at 583-5161 or matt_stevens@ncsu.edu.