- PRODUCTION -
Research conducted in 2009 over multiple locations showed potential benefits from foliar fungicides that were applied at reproductive growth stages, ranging from R5 to R6.
|By Trey Koger|
Every aspect of soybean production has centered on yield and the need to strive for constant yield improvement. This makes perfect sense as the yield of a marketable crop has always and will continue to pay the bills.
However, in 2009 after eight weeks of continuous rain, the onslaught of Phomopsis seed decay and seed rot wiped out practically 40 percent of the farm gate value of the Mississippi soybean crop. After that happened, we came to understand the importance of seed quality at harvest time. A 70 bu/A soybean crop that was 90 percent damaged and not marketable at average market selling price was virtually worthless.
Maintain soybean yield and quality
Current research funded by the MSPB on potential benefits and utility of foliar fungicides in soybean continues to focus on improving soybean yield but also on the potential benefits from foliar fungicides for maintaining seed quality at time of harvest. The focus of this research is to identify potential benefits from foliar fungicide applications coupled with warranted insecticide applications at growth stages, ranging from R5 to R6 with the objective of maintaining soybean yield and quality, resulting in a soybean crop that is marketable at current market prices.
If we can consistently improve yields with R3/R4 fungicide applications and identify methods to maintain the quality of a good yielding crop with the end goal being able to show these additional inputs provide an economic return, then we are doing a good job of judiciously utilizing grower checkoff funds. Our overall goal is to improve soybean yields and profitability.
Observations from 2009 research
Third, where we encountered measurable stink bug pressure through much of the soybean reproductive cycle (R1 to R7) coupled with wet weather for two weeks after maturity but before harvest, we saw tremendous benefits from a R5.5 application of a strobilurin fungicide application. An application of Quadris plus a pyrethroid insecticide at R5.5 resulted in minimal seed quality losses (2.4 to 5 percent damage) compared to 85 percent damage for the untreated check.
Net returns were $110/acre higher from an R5.5 application of Quadris plus pyrethroid insecticide application compared to net returns for the untreated check. This research, conducted over multiple locations in 2009, demonstrated potential benefits and utility from foliar fungicides applied at reproductive growth stages, ranging from R5 to R6. However, the overwhelming factor that influenced these potential benefits was influenced more by presence or absence of pest pressure and even more by timing of wet weather in relation to the ability to harvest the crop in close proximity to maturity before receiving significant moisture.
These late fungicide applications (R5/R6) are much more complex than the R3/R4 application, which we have always considered to be our yield enhancement application. The R5/R6 application is more dependent upon presence or absence of pest pressure and environmental conditions after the application.
Contact Trey Koger, Mississippi Extension soybean specialist at firstname.lastname@example.org.