Occurrence of arthropod pests associated with Brassica carinata and impact of defoliation on yield.

Brassica carinata has the potential to become an economical biofuel winter crop in the Southeast U.S. An IPM program is needed to provide management recommendations for B. carinata in the region. This study serves as the first steps in the developing IPM tactics documenting pest occurrence, pest position within the canopy, and the impact of defoliation on B. carinata yield. The study was performed in Jay, FL, during the 2017–2018 and 2018–2019 winter/spring crop seasons. Pest species in B. carinata were documented by plant inspection within 16 genotypes of B. carinata, and the presence of insect pests in three canopy zones (upper, medium, and lower canopy) was documented. The defoliation impact on B. carinata was evaluated by artificial defoliation. Five levels of defoliation (2017–2018 crop season: 0%, 5%, 25%, 50%, and 100%; 2018–2019 crop season: 0%, 50%, 75%, 90%, and 100%) were artificially applied during vegetative, flowering, and pod formation stages of the commercial cultivar "Avanza64." During the 2018–2019 crop season, two experiments were performed, a one‐time defoliation event and continuous defoliation. The plants were hand harvested and the average number of pods per plants, seeds per pod, thousand seed weight, and yield were estimated and correlated with defoliation levels. Results indicated the following species of pests associated with B. carinata: Microtheca ochroloma Stål (Coleoptera: Chrysomelidae), Plutela xylostella larvae, Pieris rapae L. (Lepidoptera: Pieridae), Diabrotica undecimpunctata Barber (Coleoptera: Chrysomelidae), Lipaphis pseudobrassicae Davis (Hemiptera: Aphididae), Leptoglossus phyllopus L. (Hemiptera: Coreidae), and Chloridea virescens F. (Lepidoptera: Noctuidae). The insect distribution within the plant canopy was not uniform. Different levels of artificial B. carinata defoliation did not affect seed weight, the number of seeds per pod, or the oil content of the seeds. The number of pods per plants and estimated yield were negatively impacted by defoliation during the vegetative and flowering stages. [ABSTRACT FROM AUTHOR]