At least initially, it seems that some pests were blown away by Hurricane Ian. Once such pest in my yard was the Sri Lankan Weevil. I had a small infestation that I was managing by hand-picking. The Sri Lankan weevil or Myllocerus undecimpustulatus undatus is a small white beetle that made quite a splash several years ago when it first appeared in our area. The damage this small insect does to landscape plants is very visible and can cause alert among home gardeners. Is the Sri Lankan weevil still as big a problem as it used to be?
Pest management specialists are not sure how the Sri Lankan weevil arrived in Florida, but it was first spotted in Broward County in 2000. It has since spread through most of South Florida on both coasts. The insect is a weevil, a type of beetle with a short snout-like head. A little over a quarter-of-an-inch in length, this beetle is a powdery whitish-gray color with a yellowish head – a color that really stands out against any green foliage. The adults feed on the margins of leaves notching them as they chew towards the veins. A well-chewed leave almost appears filigreed like a doily. In general, the adult beetles prefer new growth and will feed primarily in these areas. Mature, healthy plants can tolerate the damage and it is merely cosmetic in nature. Younger plants may be severely damaged. What do Sri Lankan weevils like to eat? They have over one-hundred and fifty plants on their menu. Locally some noted favorites have included citrus, lychee, green buttonwood, Hong Kong orchid tree, and the pygmy date palm.
Control can be a little tricky as the Sri Lankan weevil tends to drop to the ground and pretend to be dead when disturbed. Hand-picking can help and is very practical. If there is a heavy infestation present, one management technique involves shaking a branch over an opened umbrella catching all of the dropping weevils at one time. For chemical controls on ornamentals, carbaryl for leaf-feeding weevils will work. Make sure to read the label and apply as per label instructions. The larvae feed on roots to some degree, but not much is known about the damage caused. Any control attempts at the larval life cycle stage are not recommended.
When we had an outbreak at our demonstration garden on Harborview Road in 2008, our Indian hawthorns, some citrus and lychees were nicely notched by Sri Lankan weevils. The damage was very apparent but did not seem to overly affect the health of these woody plants. Over the years, they have pretty much disappeared from this site. We do get occasional submissions from local gardeners, but the Sri Lankan weevil population seems to have declined to a manageable level in many areas. This can often be attributed to the presence of predators and parasites which may have suppressed these weevils to a level where they are not a major problem. Now there sure could be pockets of infestations that are locally damaging but based on the number of reports of this pest insect, I think we are in a better position today.
The one good thing about most invasive pests is that they tend to plateau out and disappear into the background over time – still present, but not at a serious level. Many invasive pests make a big bang on arrival – chili thrips and the rugose spiraling whitefly, for example – but once predators and parasites build up to sufficient numbers, the pest fades into the background. We can only hope that this is the fate of the Sri Lankan weevil! For information on the control of all types of insect pests in our area, you can also call the Master Gardener Volunteer Helpdesk on Mondays, Wednesdays and Fridays from 1 to 4 pm at 764-4340 for gardening help and insight into their role as an Extension volunteer. Ralph E. Mitchell is the Director/Horticulture Agent for UF/IFAS Extension – Charlotte County. He can be reached at 941-764-4344 or firstname.lastname@example.org . Connect with us on social media. Like us on Facebook @CharlotteCountyExtension and follow us on Instagram @ifascharco.
Neal, A. (2017) Sri Lankan Weevil – Myllocerus undecimpustulatus undatus Marshall. The University of Florida Extension Service, IFAS
Mayer, H. & Mannion, C. (2011) Weevil Problems in the Landscape with Emphasis on Myllocerus undatus (Sri Lanka Weevil). Proc. Fla. State Hort. Soc. 124:301–302. 2011.
Mannion, C., Hunsberger, A., Gable, K., Buss, E., & Buss, L.(2006) Sri Lankan Weevil. The University of Florida Extension Service, IFAS