Two days remain before a weeks vacation 7-31-2014 We have Thursday and Friday remaining for field work then Friday Night, Saturday, Sunday, and Monday all have more than 50% chance of rainfall. In all likelyhood, we will have wonderful moisture going into August. Everything seems to be in good shape. Only two scenario's seem like they could need attention.
One is the cotton that started blooming during the first 10 days in July. Most has been sprayed with an pyrethroid insecticide that was planted early and I believe any field that was planted early needs to be sprayed before this rainy period sets in that could keep us out of the field for a week. Stinkbug damage is in those fields with a good boll load.
The other situation is the cotton that did not start blooming until the last 10 days of July. Most of this late cotton got a good shot of Pix this week. However, if it did not get pix on it this week and is more than 32 inches tall with no boll load, (planted after May 18th), it needs 16 to 24 ounces before it gets another inch of rain.
In the near future we should have a moth flight beginning and as cotton continues to bloom, we will figure out our August managment systems based on .....
One Spray or Two for Insects. 7-28-2014 There is not a clean overlap of stinkbugs and bollworms for the cotton in our region this year. Part of the reason is related to how much heat we have been getting which has advanced the crop ahead of average. Since stinkbugs become more important during the third week of bloom, it is not surprising that we are finding thresholds earlier, since the crop is earlier. It is a little bit surprising that the bollworm moth flight has remained low through the weekend. While it could spike up at any time, the primary explanation I have is that the corn still looks somewhat attractive and may be holding them. The main point is that the stinkbugs seem to be early like the crop while the bollworms seem to be more normal. As a result, we are probably not going to be able to take that once over shot of a combination pyrethroid spray that takes care of stinkbugs and worms, at least on the cotton that was planted early and started blooming around the fourth of July. A two spray approach for insects makes more sense on this early cotton. The late planted cotton will not reach the third week of bloom til August and is more likely to line up with the moth flight better. However, the late cotton will continue to have susceptible bolls right through the whole month of August and is likely to need a second spray based on susceptibility as well, just at different times. Continue with a strategy of scouting and spraying based on thresholds or use an approach of protecting the crop during its sensitive time which is weeks 3 through 5 of bloom as well as during a moth flight
Temperature Gradient in Region 7-26-2014 Typically we have warmer temperatures from south to north. In addtion we have warmer temperatures west to east. To quantify this, the most heat units for the season have been at Skippers Virginia at 1312 and the least heat units have been in Waverly at 1195. A difference of 50 miles represents more than a weeks difference in heat an maturity. Holland is right in the middle. The primary implication of this is the impact on the blooming and boll developement relative to planting date. I had noticed that the crop is more advanced in towns like Branchville and Boykins and along Pinnopolis Road compared to the Ivor/Wakefield cooridor and areas north. The insect developement is following a similar pattern and I am typically finding a little more stinkbug pressure on the more advanced cotton which makes since. The cotton in the more northern areas seems to have less insects but also less of a boll load. I expect that based on the heat unit model, the cotton fields along the North Carolina line and closer to I-95 will have more than half the cotton in the 3th-4th week of bloom. Cotton that has been blooming for three weeks has bolls on at least 7 fruiting branches and many second and third positions at the base of the plant. These bolls are highly susceptable to stinkbug feeding and the threshold for damage is only 10% which has not been to hard to find once it has this many bolls. Yesterday in the Wakefield area, it was much harder to find stinkbug damage as well as fields that had been blooming for over 3 weeks.
Stinkbug levels are spotty and bollworm moths have not shown up yet.
Younger Cotton Fields with only 3 or 4 fruiting branches with bolls which are typically the fields planted in the second half of May or in the more northern areas are likely going to have a better overlap of stinkbug buildup, crop sensitivity, and bollworms all occuring at the same time which should be at that typical first week of August time frame which has been when we normally have put out that first high rate of a pyrethroid. Older Cotton Early planted, Warmer areas, and otherwise fields that have been blooming 3 weeks or more which coorelates with having that 7 or so fruiting branches with bolls or blooms needs protecting either with a pyrethroid spray or intensive scouting. A number of these fields were sprayed last week and many are likely to get sprayed this week.
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