Nipaecoccus viridis (Newstead), lebbeck mealybug, (Coccoidea: Pseudococcidae), Updated Pest Alert

This Pest Alert was issued by FDACS on a mealybug with a wide range of hosts...
https://www.freshfromflorida.com/content/download/84014/2481005/pest-alert-nipaecoccus-viridis.pdf

INTRODUCTION
The first report of lebbeck mealybug in Florida occurred in 2009 where Cooperative Agricultural Pest Survey (CAPS) Specialists Andrew Derksen (DPI) and Karolynne Griffiths (USDA) collected this New Western Hemisphere Record on November 13, 2009 from Palm Beach County on host plant dodder, Cuscuta exaltata. Since then there are 89 records of this species from over 40 host plant species in four counties in Florida (Broward, Martin, Miami Dade, Palm Beach) (FDACS-DPI database). On June 14, 2019, a citrus sample with lebbeck mealybug was collected by Lauren Diepenbrock (University of Florida) (E2019-3408-1) in Highlands County, Florida after noticing heavy infestation of white wax on branches and citrus fruits (Fig. 1). This find represents a new county record and is the first occurrence of lebbeck mealybug in commercial citrus.

DESCRIPTION
Approximately 4 mm long by 3 mm wide with body color black, purple to blue green with thick white or pale-yellow wax. Females produce an ovisac (Fig. 1) with a wax that is sticky when touched. In high densities (Fig. 1), waxy secretions may appear as a continuous layer of wax which will obscure individual mealybugs. Wax may turn yellow in older infestations. Specimens do turn black in 70% alcohol. This might be a good, quick field diagnostic, but species confirmation will require slide mounting (Stocks and Hodges 2009). For pictures visit the link above.

HOST PLANTS AND GEOGRAPHICAL DISTRIBUTION
 It has been reported from over 45 host plant families including several species of citrus from at least 63 countries all over the world. (García Morales et al., 2016).

ECONOMIC IMPORTANCE
This is an agricultural pest in many parts of the world on a variety of agricultural crops. In Florida, citrus, cotton, ornamentals and tropical plants would all be potential impacted crops. In citrus growing areas of Jordan, where this insect had been a pest prior to introduction of biological controls, it caused such extensive damage that groves were burned in an effort to eradicate it (Stocks 2013). Losses in citrus groves are mainly due to premature fruit drop. In South Africa, infested citrus acreage demonstrated losses of up to 50% of the crop (Cilliers and Bedford, 1978).

How Does Mulching in Large Ornamental Production Containers Compare with Preemergent Herbicides?

Season long weed control in large containers that may take six months to a year to finish can be very challenging.  Preventing weed emergence and seeding is critical to maintaining a clean crop and reducing costs.   

We wondered if we could spread a relatively cheap biological mulch over the top of large production containers to reduce weed growth relative to spraying or applying a preemergent herbicide.  We also considered an addition of a tackifier which is a glue to hold down mulch particles for better weed control.

Dr. Chris Marble of UF/IFAS Mid-Florida Research and Education Center and I applied for and received a USDA Southern Sustainable Research and Education On-farm Grant to test the idea.

At four locations and multiple crops, we tested an assortment of mulches:  pinebark, shredded wood, paper slurry, pinebark with paper slurry, sawdust, and we tested with and without the tackifier on all those mulches.  In addition, we included a plastic mulch; the same as vegetable or strawberry growers use. We also included no mulch and a preergent herbicide as controls to see differences.

After a couple of years of research we learned a few things.  All mulches stopped weeds from germinating from the surface soil in the pot early after application.  The more successful mulches over time prevented blown in weed seeds from finding a good spot to become hydrated and gain a foothold on the surface. Plastic mulch was the best followed by large pine bark.

Tackifier had no effect on the mulch performance.

Here is a video of the research that summarizes the work we were able to accomplish.
https://drive.google.com/open?id=1AGjuMfqFqhpF667ZPPmOuKH9oqmDJpvR

For a poster style summary you can click here:  https://drive.google.com/open?id=1nPp45rOSFK61ShBU_JwE-VEbR813uA0F

I would like to give a special thanks to Greg Shiver at J&R Nursery and Vincent Tort at Sun City Tree Farm for their on-farm help and USDA SSARE for the funding.