What is in this article?:
- Consultant survey paints North Carolinaâ€™s 2013 cotton insect picture
- Stink bug damage
- Where did the bollworms go?
• Consultant responses to our insect survey questionnaire are both an accurate account of the past “insect year” and represent approximately one third of North Carolina’s total cotton acreage.
Where did the bollworms go?
What happened to bollworms?: Bollworm damage to bolls was lower in 2013 than in any year of my damaged boll survey — which began in 1985. Certainly, 2 gene Bt cotton has helped significantly in lowering bollworm and other caterpillar damage.
Bollworms emerge initially from the soil as moths in the spring (most often in May). They subsequently undergo 2 generations, the first on whorl stage corn (and other hosts) and the next generation on silking stage corn.
For all generations, an underground pupal stage is necessary. As we determined in the mid-1970s, pupal cell integrity is important in the survival of this stage.
One might guess that a high proportion of pupal cells were destroyed in many areas of the state due to our extended rainy weather and saturated soil conditions.
All the consultants surveyed indicated stink bugs were the primary driver of late-season applications in 2013, with bollworms a non-issue for most. This was the first year I recall that so many light traps reported zero moths during consecutive days during our “major” bollworm moth flight.
Cotton aphids and spider mites: Consultant surveys, calls and our own observations indicated that we got a break from other insect pests in 2013, with 3.4 and 1.4 percent of consultants’ clients’ acreage being sprayed for spider mites and cotton aphids, respectively.
Cotton aphid colonies were few and far between, while the moderate level of spider mites calls and reports often revealed populations that did not reach treatable levels, probably in part a result of our generally high rainfall and humidity in 2013.
Insect pest predictions for 2014: In trying to predict what producers can expect in the way of insect pests in 2014, for soybeans it’s easy: More kudzu bugs.
Based on many years of experience, for cotton two points come to mind:
• We don’t have a clue about 2014.
• The expense of scouting- and threshold- based decisions pays for itself many times over.