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Commercial Horticulture > Comm Hort Blog > Posts > CONTINUE TO MONITOR SUGARCANE BEETLES IN SWEET CORN

There have been many reports on sugarcane beetle damage to corn in Alabama. Readers can look back at the first issue of IPM COMMUNICATOR to refer to Dr. Kathy Flander’s report on sugarcane beetle activity. Since grower concern is still there, below is some more info on the insect pest for improving correct diagnosis.

What is Sugarcane Beetle?  It is a black, hard bodied beetle (1/2 inch long) with short spiny legs that look like oars. The legs are used for digging into soil and the beetle moves across the soil surface slowly. If you look at a beetle closely, you may notice that it will try to dig into the soil rather than move across an open surface probably to avoid predation and desiccation. The beetle lays eggs in soil that hatch into grubs with bright red head, brown legs and dark abdomen. Growers need to look very carefully into the soil if crop lodging is noticed along with signs of chewing in the bottom of the corn stalks (see picture on the side).  Late-season BEETLES will overwinter in soil (after August) and resume activity in early spring the following year. There is one generation of the insect per year.
Monitoring:  According to Dr. Flander’s article the peak activity period (around May 10th) is over now but the replanted corn may be attacked. North Carolina Extension suggests activity period from April 15 to June 15, which is interesting. Light traps are good for attracting beetles. It is good idea to take a shovel and dig up corn at different places throughout the field and directly look in the soil for soil pests.
What can confuse growers?  Ground beetles that are predators are somewhat larger that sugarcane beetles and move rapidly over soil surface using long slender legs (less tendency to dig into soil). May beetles are large in size and very plump. Dung beetles are somewhat flatter than sugarcane beetles and can fly very well. SEND BEETLE SAMPLES TO THE AUBURN DIAGNOSTIC LAB TO CONFIRM PEST ID.
Host plants:  Sugarcane beetle feeds on corn, sweet potatoes, sugarcane and rice. Beetles can also feed on cotton, strawberry, roses and wild grasses if given a chance (NCSU Extension info).
IPM tactics:
· Damage is also more likely in crops planted in former sod fields or if corn is planted close to sod fields.
· Plant early and follow proper fertilizer rates to optimize crop establishment and rapid growth. Damage appears to be greater in short crop compared to the tall crop.
· Planting-time chemical treatment: First make sure you have the sugarcane beetles in your crop by scouting properly. Contact a Regional Extension Agent based at County Offices across Alabama for correct technical information and bring samples of insects to them for proper identification. Remember that there are many insects that may look like sugarcane beetle. Growers can spray pyrethroid insecticides like lambda-cyhalothrin (e.g., Warrior @ 4 oz/A), gamma-cyhalo (e.g., Proaxis @ 4 oz/A), or Bifenthrin (e.g., Tundra @ 4-5 oz/A depending on row spacing) in sweet corn. Check with your pesticide dealer for other products and keep the 2010 Southeastern Vegetable Crop Handbook handy this year for reference. The goal with insecticide sprays should be to apply insecticide at the base of the stalk where the beetle may contact the chemical.
· Pre-plant incorporation of chlorpyrifos (Lorsban 4E @ 4 pt/A) may protect the crop. Seed treatment with clothianidin (Poncho) or imidacloprid (Gaucho) may work for a limited time period.
· Finally, TURN OFF THE LIGHTS! To read about light usage around the farm read Dr. Blake Layton’s interesting article at http://msucares.com/newsletters/pests/bugwise/2009/bw0209.pdf . 

 

 

Ayanava Majumdar
Extension Entomologist
bugdoctor@auburn.edu


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