Impact of selected adjuvants combined with Vantacor against the sugarcane borer, 2023

Authors: Penn, Hannah; Richard, Randy; OGERON, ALBERT - Louisiana State University Agcenter

Submitted to: Arthropod Management Tests
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/8/2024
Publication Date: 5/17/2024
Citation: Penn, H., Richard, R.T., Ogeron, A.J. 2024. Impact of selected adjuvants combined with Vantacor against the sugarcane borer, 2023. Arthropod Management Tests. https://doi.org/10.1093/amt/tsae067.
DOI: https://doi.org/10.1093/amt/tsae067

Interpretive Summary: Sugarcane borer or SCB is the main insect pest of sugarcane in Louisiana, decreasing levels of produced sugar if not treated. The primary insecticide used in the past two years to control SCB is Vantacor, a recent replacement of a previously used insecticide (Prevathon) that is more concentrated. With the recent release of product, the best adjuvant to use with it is not known though the manufacturer recommends a methylated seed soil (MSO). This study compared the amount of SCB damage using Vantacor with three different adjuvant products (Destiny HC [a MSO], InterLock, and Latron AG-98) and untreated controls. To measure this, we sprayed a second ratoon sugarcane field in June 2023 using a drone sprayer. SCB injury was measured before to harvest by counting the total number of internodes on a stalk and the number with holes. The number of internodes was then broken up by stalk thirds to find SCB injury at different times of growth. Plot weights and juice contents were collected and used to calculate sugar yield. We found that when Vantacor was combined with InterLock, it controlled SCB early in the growth period and throughout grand growth of the sugarcane better than Latron AG-98 treated and plots that were not treated at all for SCB. Destiny HC did not significantly differ from either InterLock, Latron AG-98, or the untreated controls during these times. We did not see any treatment differences in SCB injury late in the growing season or when all damage was combined. We also did not find any differences between treatments in juice contents or yield. This study shows that spraying Vantacor can control SCB, particularly when combined with the adjuvant InterLock. However, further uses with a backpack or ground sprayer rather than a drone should be assessed.

Technical Abstract: Sugarcane borer (Diatraea saccharalis), SCB, is the primary pest of sugarcane (Saccharum spp.) grown in Louisiana, substantially decreasing sugar yields if infestations are left unmanaged. The most commonly used insecticide in the past ten years for SCB was Prevathon (active ingredient chlorantraniliprole), but this formation was recently replaced by the more concentrated Vantacor (active ingredient chlorantraniliprole). Given that Vantacor was only recently release, the optimal adjuvant to add when spraying to ensure good SCB control has not been widely assessed. This study assessed SCB control differences when Vantacor was applied with one of three adjuvants: Destiny HC (a methylated seed oil as recommended by the Vantacor manufacturer), InterLock, and Latron AG-98. These combinations were compared against untreated controls. All treatments were applied using an aerial spray drone in June 2023 to a second ratoon sugarcane field planted in HoCP 00-950, a SCB-susceptible cultivar. SCB injury was assessed prior to harvest by determining the percentage of bored internodes which was then calculated for the bottom, middle, and top third of the stalk to better indicate SCB injury timing. Damage to the bottom indicates early-season damage, middle damage indicates damage during grand growth, and top damage indicates late-season damage. Plot weights and juice contents were collected and used to calculate cane tonnage and sugar yield. We found that the total number of bored internodes was not differ among treatments. However, Vantacor when combined with InterLock significantly decreased SCB injury relative to untreated controls and Latron AG-98 throughout early and grand growth periods. No treatment differences were seen late in the season. We did not observe any differences in juice contents or yield metrics. Our data indicate that, of the tested products, Vantacor was most effective when applied with InterLock. However, because these products were applied with a drone at a low GPA, further use with a backpack or ground sprayer should be assessed.