The plant bug situation has not changed over the past week. There are still some hotspots with high numbers of nymphs, but overall populations are manageable. We have also observed and received reports that adult plant bugs are showing back up in places, presumably moving in from nearby corn fields. When scouting, keep an eye out for borders with corn because that is likely to be where the highest pressure is. We have reached the point of the season where a sweep-net may be needed in addition to a drop cloth as nets are more efficient in picking up adults. Managing these populations of adult plant bugs is important because they will also be depositing eggs that will hatch out in the following 7-10 days. Keep scouting for plant bugs and be prepared to treat when needed.
Spider mites should be in the back of everyone’s mind right
now. Spider mites have been reported at treatable levels in NE and SE Alabama
this week, and we have observed populations in fields in central Alabama as
well. The current long-range forecast doesn’t look favorable for soaking rains,
which help beat spider mite populations back. At this point in the season, we recommend
using higher rates of abamectin for controls. There are two formulations of
abamectin sold (0.15EC and 0.7EC). Higher rates (12oz+ or 3oz) provide more
consistent control in bigger cotton with a lot of canopy. Based on the current
forecast, I could suggest being proactive on a spider mite infestation,
particularly if going across the field anyway. Spider mite infestations are
much easier to control before they “get out of hand.”
We have also heard about a few fields in south Alabama with
escape worms in Bollgard 2 (BG2) cotton. We do not believe this is widespread,
in other words, I wouldn’t start automatically treating all my BG2 fields, but
we should be aware. Our threshold is when 5% small larvae (5 worms on 100
plants) or when 6% damage is observed (squares, flowers or bolls). There are
several options for control, however they are all most effective when applied
to small worms (>0.25”). We know there is some bollworm pyrethroid
resistance, however, they may provide adequate control in some cases. The
diamides (Besiege, Vantacor, Elevest) provide the best control, but at a price.
If a pyrethroid is used, it should be monitored closely after application because
the cost of a “miss” could be high.
Where are the stink bugs? That is one of the biggest
questions we are getting right now. My answer is, I don’t know, but I hope they
stay where ever they are. In general, there just hasn’t been a whole lot of
stink bugs or damage observed in fields so far. It could be that we were more proactive
in corn this year, or on plant bug management, or it could be related to weather
somehow. Whatever the reason, we know the high damage potential stink bugs have
and we need to continue scouting and be prepared to intervene when necessary.
Things have been very quiet on the soybean and peanut front.
We have talked to a several folks this week and there doesn’t appear to be much
action out there. There are some cloverworms in most fields, a few loopers and
stink bugs here and there, but overall, not much. This highlights the
importance of scouting and only treating when necessary. If there are no damaging
levels of pests in the field, then there is no return on an insecticide
application.
As always, if we can ever be of any help, or if you would like to
provide input on the situation in your area, please don’t hesitate to reach out
(Scott Graham: 662-809-3368; Ron Smith: 334-332-9501). For more information on
thresholds and insecticide recommendations, visit the Alabama Cotton IPM Guide
(IPM-0415). To
stay up-to-date on the Alabama cotton insect situation, subscribe to the
Alabama Cotton Shorts Newsletter, Alabama
Crops Report Newsletter, and the
Syngenta Pest Patrol Hotline.
