Updates from Bob Kemerait about potential tropical storm and cotton target spot.
Potential Tropical Storm
Most important for this morning (7/8/19): watching the potential development and buildup of a tropical system in the northern Gulf of Mexico that could bring storms to us late in the week. While the extent and impact of the development of the system is unclear now, it could have significant impact on disease management in Georgia. Please relay to your growers that systems like this (wind and rains) can have 4 major impacts on row-crop disease management.
- Rains create perfect moisture for further disease development and spread. We are at a time in the season when we already have some disease (soybean rust, southern corn rust, white mold, leaf spot, and target spot) present and also the crops are developing to more-susceptible growth stages.
- Winds from storms could further spread diseases by moving spores, especially rust diseases.
- Abundant rains could keep growers from making timely fungicide applications and keeping them from getting back into the fields.
- Delays in applications could further increase disease problems in the fields.
Target spot of cotton could thrive now: Priaxor is our best fungicide for managing target spot and also most reliable. But certainly not the only one. I know azoxystrobin is labeled and it is also effective against target spot, but under pressure does not do as well. If I look back at trial data, often a single application of Priaxor provides the control of two applications of azoxystrobin. In deciding when to spray and what to spray, look at 1) crop development- has it started to bloom?, 2) how is crop growth- it the crop developing well with good yield potential?, 3) are conditions favorable for disease and are you finding target spot in the bottom of the canopy?
2018 Cook Co Peanut Fungicide Program Trial Info