Strengthening Organic Farming in the Southeast Project: Research Summary from Mississippi State University, 2018

Dr. Casey Barickman

In the spring of 2018 three squash varieties (Gentry, Spineless Beauty, and Zephyr) and 3 southern cowpea varieties (Coronet, Queen Anne, and Mississippi Silver) were planted at the experiment station at Mississippi State University to investigate effects of three OMRI-approved organic pesticides on their yields. The organic pesticides tested were: Pyganic (Pyrethrin); Entrust (Spinosad); and Neemix (Azadirachtin). This report summaries preliminary findings at the North Mississippi Research & Extension Center. 

1. Squash was transplanted onto black plastic covered rows on May 31 and harvested for the first time on June 18. In all eight harvests were made.  

2. Southern peas were direct seeded on May 30 and the first harvest was on July 23. In all four harvests were made. 

3. The only difference between the organic pesticide treatments was in the fancy squash category where Neemix had significantly lower yields than the control. Also in the squash cull category Neemix had significantly more culls than Pyganic. Neemix oil did have the highest yields in the marketable squash category but not significantly higher than all other treatments. Southern pea varieties had no significant difference among the organic pesticide treatments in yields, however the Neemix treatment had higher pod and pea weights. Among the varieties, Gentry out performed Spineless Beauty and Zephyr in the fancy grade and Zephyr had significantly more marketable squash then Gentry or Spineless Beauty. The southern pea Coronet yielded the highest total pod and pea weights but only significantly higher that Queen Anne. 

4. Conclusion: Summer squash and southern pea varieties had the greatest impact on determining yields. There were no significant differences between organic pesticide treatments for marketable squash or for pea yields. The highest yielding squash variety Gentry, a yellow crookneck squash, has a history of being one of the earliest and highest yielding varieties. We had lower than expected insect pressure much of the season and fairly mild weather in north Mississippi in June and July of 2018. We are planning to repeat this study in 2019 and 2020.