Impact of insecticide, rate, and timing combinations against sugarcane borer, 2019-2020

Authors: Penn, Hannah; Richard, Randy; Johnson, Richard

Submitted to: Arthropod Management Tests
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/3/2023
Publication Date: 5/19/2023
Citation: Penn, H., Richard, R.T., Johnson, R.M. 2023. Impact of insecticide, rate, and timing combinations against sugarcane borer, 2019-2020. Arthropod Management Tests. 48(1):1-2. https://doi.org/10.1093/amt/tsad055.
DOI: https://doi.org/10.1093/amt/tsad055

Interpretive Summary: Sugarcane borer or SCB is the main insect pest of sugarcane in Louisiana, decreasing levels of produced sugar if not treated. The most commonly used insecticides in the past ten years to control SCB include Confirm and Prevathon. This study compared using higher rates of both products but sprayed earlier in the year to lower application rates sprayed when 5% of sugarcane stalks with have SCB larvae present in leaf sheaths. To measure this, we sprayed a plant cane field in 2019 and the same field as 1st ratoon in 2020. SCB injury was measured before to harvest by counting the total number of internodes on a stalk and the number with holes. Plot weights and juice contents were collected and used to calculate sugar yield. We found that in 2019, Prevathon successfully controlled SCB compared to plots that were not treated at all for SCB. While Confirm-treated plots had less SCB damage than untreated plots, it was not significant. There were no differences in SCB damage due to application amount or timing. We also did not find any differences between sprays in yield. Like the prior year, in 2020, we did not see any differences in SCB damage or yield due to low levels of SCB. This study shows that spraying Prevathon can control SCB. However, now that a new product (Vantacor) is replacing Prevathon, we will need to redo this study on how to control SCB.

Technical Abstract: Sugarcane borer (Diatraea saccharalis), SCB, is the primary pest of sugarcane (Saccharum spp.) grown in Louisiana, substantially decreasing yields if infestations are unmanaged. The most commonly used insecticides in the past ten years for SCB treatment include Confirm (active ingredient tebufenozide) and Prevathon (active ingredient chlorantraniliprole). This study assessed if using higher rates of these two insecticides early in the growing season would better control SCB populations relative to lower rates applied at SCB threshold (5% of stalks with larvae present in leaf sheaths). A sugarcane field planted in HoCP 09-804 was assessed as plant cane in 2019 and 1st ratoon in 2020. SCB injury to sugarcane was assessed prior to harvest by determining the percentage of bored internodes. Plot weights and juice contents were collected and used to calculate cane tonnage and sugar yield. We found that in 2019, Prevathon significantly reduced SCB injury relative to untreated controls. While Confirm-treated plots had less SCB damage than untreated controls, it was not significant. There were no differences due to rate and timing for either insecticide. Further, we did not observe any differences in juice contents or yield metrics in 2019. Similarly, in 2020, we observed no differences any metrics, potentially due to low SCB pressure. Our data indicate that Prevathon is an effective control measure for SCB, and the tested rates and timing did not impact damage. However, further evaluation of a new concentrated formulation of chlorantraniliprole, Vantacor, meant to replace Prevathon should be conducted.