by Kenneth Gravois, LSU AgCenter
The West Indian canefly is a sporadic pest of sugarcane in Louisiana that establishes after a mild winter, such as this past winter of 2015-16. The canefly is a piercing/sucking insect that feeds on plant sap and excretes honeydew, which promotes the growth of sooty mold on the leaves and leaf sheaths.
The loss of sap reduces turgor pressure in the plant, and the sooty mold can negatively affect photosynthesis. Late infestations can decrease the efficacy of ripeners when applied to the crop.
Research has been conducted to demonstrate that high populations of the West Indian canefly are a yield-limiting pest of sugarcane in Louisiana.
In 2012, sugarcane in Louisiana experienced high infestations with the West Indian canefly. A crisis exemption under Section 18 for imidacloprid for the control for West Indian canefly in sugarcane in Louisiana was granted by the Louisiana Department of Agriculture and Forestry (LDAF) for the period August 7 – August 21, 2012. Imidacloprid was effectively used to control yield-limiting infestations of the canefly.
In 2013, a specific exemption under Section 18 was applied for and was granted for the use of Admire Pro for the control of the West Indian canefly in sugarcane in Louisiana. Admire Pro (imidacloprid) is manufactured by Bayer Crop Science, whose support for the Section 18 is critical.
A series of freezes in late February effectively reduced populations of the West Indian canefly, and the use of insecticides to control the canefly was not needed.
Since early 2016, agricultural consultants have been observing populations of the canefly along with numerous egg masses. Work on a Section 18 began in March, knowing that a submission would eventually be needed.
A specific exemption under Section 18 of the amended Federal Insecticide, Fungicide, and Rodenticide Act for the use of Admire Pro for the control of the West Indian canefly in sugarcane in Louisiana was submitted to the LDAF on May 26, 2016. LDAF had to format the document and gather some additional information.
The Section 18 was submitted to EPA on May 31, 2016. EPA quickly acknowledged receipt of the Section 18 and has also requested additional information, which is currently being gathered.
Admire Pro is classified as a neonicotinoid insecticide, a class that is under tremendous scrutiny at the moment due to potential negative effects on honey bees and other pollinator insects. We have emphasized to EPA that sugarcane does not flower and is a tall crop – two factors not conducive to harboring pollinator insects.
Many have asked that LDAF request a crisis exemption immediately. After discussion among AgCenter scientists and crop consultants, we have decided not to immediately pursue this route. Remember that a crisis exemption is only for 15 days; we want to use this option at the most appropriate time. This certainly remains an option for the future.
If you have high populations of West Indian canefly, the best option at the moment is spot applications of Karate (lamda-cyhalothrin) or Prolex (gamma-cyhalothrin).
An insecticide application should be made when West Indian canefly populations are increasing for two consecutive weeks and average ~30 nymphs/leaf with honeydew and sooty mold building up in the upper canopy at the time of treatment.
Sugarcane Ag Consultants are well versed on the principles of integrated pest management. Applications of pyrethroids early in the growing season can spike aphid infestations as well harm beneficial insect populations that keep the sugarcane borer in check.
AgCenter scientists (Drs. Julien Beuzelin and Blake Wilson) and USDA-ARS research technician Mr. Randy Richard are currently mapping West Indian canefly infestations in the Louisiana sugarcane growing areas and conducting insecticide efficacy trials.
The objective of this work has the short-term goal of supporting the current Section 18 request, and the long- term goal of obtaining full registration status of an insecticide to effectively control West Indian canefly and other aphid pests of sugarcane in Louisiana.
Everything reported here is a cooperative effort involving scientists from the LSU AgCenter and USDA-ARS Sugarcane Research Unit, the sugarcane crop consultants, and representatives of LDAF. We welcome any and all feedback.