The Apopka Weevil has Become Established in North Florida Citrus

The Apopka Weevil has Become Established in North Florida Citrus

Russ Mizell and Xavior Martini, UF/IFAS Entomologists, NFREC, Quincy

Citrus production in North Florida is expanding rapidly in response to the devastation of citrus in Central and South Florida due to citrus greening disease. Citrus acreage in southern Georgia is also increasing. Florida’s climate is situated in the temperate (North) and subtropical (Central and South Florida) regions. Thus, non-native pests from other similar habitats around the world can and frequently do become established in Florida. For example, some non-native pests of citrus that are well established in subtropical Florida include Diaprepes abbreviatus, better known as the “Apopka weevil,” the sugarcane rootstook borer, and the Sri Lanka weevil, Myllocerus undatus. Both of these weevils feed on citrus leaves as adults and their immature stages feed on the roots. Both species also feed on a wide range of other plant species damaging leaves and roots.

The annual low temperatures observed in North Florida the last few years have been higher, possibly due to climate change, and as a result have enabled some pests usually restricted to the subtropical areas of Florida to expand their ranges into the North Florida temperate zone. In addition, expansion of citrus culture with the corollary acceleration of plant movements across the state increase the risk of pest introduction from southern parts of Florida.

Via this article, we are alerting extension personnel, home gardeners, and more specifically citrus growers and nurserymen that D. abbreviatus has been detected for the first time recently in an established population in Jefferson County, FL. Diaprepes abbreviatus has several hundred known host plants including citrus, sugarcane, vegetables, fruits and many woody landscape plants. Sicklepod, Senna obtusifolia, and pokeweed, Phytolacca americana, appear to be favorite adult hosts in north Florida in August-September. The large black and white-striped and often orange colored adults (Fig. 1 – C and 1D) feed on fresh leaves where they place their white egg masses in pouches (Fig. 1 – A)  made from 2 leaves connected together. The larvae (Fig. 1- B) hatch and fall to the ground where they feed on plant roots often at depths of 1-2 feet or more. There are 2 generations per year in southern Florida, but the number and timing of those that will occur in north Florida remains unknown.  Adult weevils are easily detected, and often occur as mating pairs. They are not known to be great fliers; however, the larvae can be found in, and be spread around while infesting plant roots in containers.

Diaprepes abbreviatus more commonly called Apoka Weevil

Fig. 1: Diaprepes abbreviatus (A) eggs (B) larva, (C) orange form adult, and (D) white form adult. Picture by Tai Huang (A) and Lyle Buss (B, C and D).

This weevil is a quarantined pest, so nurseries in infested counties are required to follow specific insecticide treatments prior to shipping outside of the quarantine area.  Producers of any potentially infested crops should monitor visually for the adult weevils by looking for feeding damage and adult weevils on the crop and associated weeds.

Further information on this insect pest can be found in the following UF/IFAS publication:  Diaprepes Root Weevil, Diaprepes abbreviatus.  

Brown Marmorated Stink Bug Control Using Natural Enemies

Brown Marmorated Stink Bug Control Using Natural Enemies

A few weeks ago I was lucky enough to attend North Carolina State’s Tomato Field Day, at the Mountain Horticultural Crops Research and Extension Center in Mills River, NC.  Every summer crowds flock from all over the Southeast to learn what’s new in the world of tomatoes.  Since it’s not always convenient for you to drop what you’re doing to make a road trip to North Carolina, I’ll highlight something I learned from the field day.

Stink Bug Control by Dr. Jim Walgenbach

Distribution

The brown marmorated stink bug (BMSB) was introduced into the United States from Asia.  The insect pest was first found in Pennsylvania and is suspected to have made its way to the US in packing material.  BMSB was first reported in 2009 in Hillsborough County, FL and since been found in additional Florida counties.  It has a wide host range including fruits, vegetables, and ornamentals.

Fifth instar nymph of the brown marmorated stink bug

Fifth instar nymph of the brown marmorated stink bug on raspberry in Allentown, Pennsylvania.  Photo Credit: Gary Bernon, USDA-APHIS

Identification

BMSB has a typical stink bug body shape and size with a mottled brown coloring.  The key identification feature is alternating dark and light bands on the last two antennal segments.

Trissolcus japonicus adults.

Trissolcus japonicus adults. Female to the left; male to the right. Photo Credit: FDACS – DPI

Biological Control with Natural Enemies

Dr. Walgenbach’s team is currently researching the impact of suppressing BMSB populations by native predators such as: katydids; jumping spiders; earwigs; and lady beetles.  Current observations indicate only a minor effect from these predators on BMSB.

Parasitized BMSB

BMSB egg masses parasitized by T. japonicus. Photo Credit: Matt Lollar, University of Florida/IFAS Extension.

Trissolcus japonicus Assessment

A regional effort has been implemented to monitor the introduction, spread, and efficacy of the Asian parasitoid Trissolcus japonicus.  Trissolcus japonicus is a tiny wasp that parasitizes the eggs of various stink bug species.  It was first collected from China and brought back to quarantine facilities in the US for evaluation, as a potential biological control agent.  Host-specific tests have indicated that T. japonicus prefers to parasitize BMSB eggs over eggs of other stink bug species.  It is suspected that release permits for the wasp will be available from the USDA in the near future.

Reporting in Florida

The brown marmorated stink bug overwinters in homes to keep warm.  If stink bugs are found in yuor home, they may be the BMSB and should be reported to the Florida Department of Agriculture and Consumer Services Division of Plant Industry.  Specimens should be collected for identification.

To follow the research of Dr. Walgenbach and his colleagues, please visit NC State’s Entomology webpage.

The Bumble Bee – One of Florida’s Vital Pollinators

The Bumble Bee – One of Florida’s Vital Pollinators

Bumble bees and other pollinators often visit the vast fields of cotton flowers in north Florida’s agricultural lands. Although cotton is mainly self-pollinating, pollination by bees can increase seed-set per cotton boll. Note the pollen grains stuck on each bee. Photo by Judy Biss

Bumble bees and other pollinators often visit the vast fields of cotton flowers in north Florida’s agricultural lands. Although cotton is mainly self-pollinating, pollination by bees can increase seed-set per cotton boll. Note the pollen grains stuck on each bee. Photo by Judy Biss

Bumble bees are among the most recognizable of insects. They are large, colorful, and a wonder to watch.  They’re also popularized in media, cartoons, and clip-art images, but beyond the popular images, bumble bees are worthy of our attention as important pollinators of both native plants and agricultural crops.  They are one of hundreds of pollinating bees that are critical to the abundance of our native lands, wildlife, and also our food supply.  Protection of pollinators has received national recognition and many programs are now geared towards pollinator conservation. 

Why is Pollinator Protection Important?

According to the UF/IFAS publication Minimizing Honey Bee Exposure to Pesticides:

The western honey bee is conceivably the most important pollinator in Florida and American agricultural landscapes. The honey bee is credited with approximately 85% of the pollinating activity necessary to supply about one-quarter to one-third of the nation’s food supply. Over 50 major crops in the United States and at least 13 in Florida either depend on honey bees for pollination or produce more abundantly when honey bees are plentiful.

And:

“Growers also use other managed bees species, such as the bumble bee to provide field and greenhouse crop pollination services. Additionally, there are more than 315 species of wild/unmanaged bees in Florida that play a role in the pollination of agricultural crops and natural and managed landscapes. These include mining bees, mason bees, sweat bees, leafcutter bees, feral honey bees, and carpenter bees, among others.”

Pollinator Protection was formally recognized at the federal level in 2014, when the President of the United States signed an official memorandum entitled: Creating a Federal Strategy to Promote the Health of Honey Bees and Other Pollinators  which outlines specific steps to increase and improve pollinator habitat. These steps are geared towards protecting and restoring populations of not only honey bees, but native bees, birds, bats, and butterflies; all of which are vital to our nation’s economy, food production, and environmental health.

Bumble Bee Biology and Ecology

There is much to learn about these fascinating insects.  Here are some facts to feed your curiosity.  Additional resources are listed at the end of this article.

  • Bumble bees belong to the genus Bombus within the family Apidae. As such, they are related to honey bees, carpenter bees, cuckoo bees, digger bees, stingless bees, and orchid bees.
  • There are about 50 species of North American bumble bees.
  • Bumble bees are social and form colonies like honey bees do, but bumble bee colonies are smaller (50 – 500 individuals), and their colonies only last one season.
  • Bumble bees generally make their nests in the ground, using abandoned rodent cavities or under old tree roots, etc.
  • Each spring, a mated queen emerges from winter hibernation and finds a suitable underground cavity. She begins collecting nectar and pollen and laying eggs to build her colony.
  • By late summer and into fall, the only surviving member of the colony are new queens.
  • These queens mate and then they hibernate during winter 2-5 inches deep in the soil. The following spring these queens emerge and start new colonies, repeating the annual cycle.
  • Bumble bees are adapted to a wide range of environmental conditions and can forage in cooler, cloudier, and wetter weather better than other bees. Because of this adaptation, they are generally the first bees out in early spring and the last bees out in the fall.
  • Since bumble bees are adapted to a wide range of environmental conditions, they are also able to feed on a wide variety of flowering plants.
  • Bumble bees do make honey, but only enough to feed the colony during bad weather, when they are unable to go out and forage.
  • Bumble bees, like the blueberry bee collect pollen from certain flowers using a unique behavior called “buzz pollination,” or “sonication.” This behavior is not found in European honey bees. Some plants, blueberries for example, hold tightly to their tiny pollen.  Bumble bees and blueberry bees grab the flower structure and powerfully vibrate their wings while holding onto the flower.  Their whole body vibrates and literally shakes the pollen lose from the flower.
  • Bumble bees are so effective at pollinating important food crops, they are raised commercially and sold to pollinate produce such as tomatoes, peppers, cranberries, and strawberries.
Bumble bees busy at work on our native flowers. Photo by Travis MacClendon. Calhoun County Florida Wasps and Flies

Bumble bees busy at work on our native flowers. Photo by Travis MacClendon. Calhoun County Florida Wasps and Flies

Create Your Own Pollinator Pasture

You can help increase the abundance and health of bumble bees, other native pollinators, and honey bees by creating nectar and pollen rich bee pastures.  These pastures can be filled with annual plants, which grow from seed each year, perennial plants, which return and spread on their own each year, various flowering shrubs and trees, or any mixture of above. You can also manage existing natural areas and woodlands by employing recommended prescribed fire regimes, non-native invasive plant control, and other practices to encourage a diversity of native pollinator plants.

The ideal bee pasture is one in which flowers are blooming as continuously as possible throughout the year. Research shows bees thrive best in open sunny pastures that are as large as possible, with a diversity of plants types. While flowering shrubs along woodland edges are well used by bees, a bee pasture that is allowed to become dominated by trees and shade will become less attractive to bees. A dedicated, open, sunny pasture having nectar and pollen plant diversity is best.  Just as with any field you intend to plant, the first step is to collect a soil sample for analysis of existing nutrients and pH levels. (For more information on soil samples read the article Soil Test First!

Pollinator Plant Types

There are many plants that provide nutritious nectar and pollen for North Florida’s pollinators. Some examples of plants which are good pollinator food sources are maple trees, redbuds, poplars, gallberries, blackberries, palmettos, partridge pea, mint, thistles, goldenrod, asters, tickseeds, sunflowers, squash, melons, and clovers. If you purchase a bee pasture blend from a seed company, make sure it is suited for growing in North Florida and does not contain noxious, invasive, weedy plant species. The Florida Exotic Pest Plant Council maintains a listing of documented invasive plants here: List of Invasive Plant Species.

Summary and Resources

The business, biology, and botany of pollination is fascinating and critical to sustainable and diverse food production in Florida and the United States. Bumble bees are just one of the many native pollinators that frequent our forests, fields, and gardens.  Consider turning your fallow lands or backyards into productive bee pasture and reap a sweet harvest.

For more information please see the resources used for this article below:

 

Art, Garden & Farm Family Festival – October 6

Art, Garden & Farm Family Festival – October 6

Bring the whole family for a fun day at the NFREC Art & Garden Festival and talk with agricultural scientists about new crops, methods and equipment for modern farming.

As the weather cools and plants perk up, join us for a day of fun activities for the whole family! View farm animals and equipment, and talk with agricultural scientists about new crops, methods and equipment for modern farming. Take a stroll through the new botanical garden or hop on a tractor-trolley for a tour highlighting fruits and nuts for our area. Speak with experts about all your gardening questions, or purchase unusual, hard-to-find, top-performing plants for your garden.  Children’s arts and crafts activities will take place in a huge “Kid Zone” located in a shaded area of the garden area.  Local arts and crafts will be for sale, and food and beverages will be available.

The University of Florida/IFAS will host the Art, Garden & Farm Family Festival on Saturday October 6, at the North Florida Research and Education Center (NFREC), Quincy Campus. The event will be held form 9:00 am to 2:00 pm EDT. NFREC Quincy is located off Pat Thomas Highway, State Road 267, at 155 Research Road, Quincy, FL, just north of I-10 Exit 181,  or three miles south of Quincy, Florida.

The event is free and open to the public.  For more information: http://nfrec.ifas.ufl.edu/art-and-garden/

Friday Feature:  Weed-Killing Robots

Friday Feature: Weed-Killing Robots

This week’s featured video was produced by ecoRobotix to show how their autonomous robots control weeds in crop fields with micro-doses of herbicides.  Their self-propelled robots are solar powered, and use a plant-recognition camera to guide targeted, and precise applications of herbicides to the weeds detected amongst the crop plants. Thanks to Dr. Pete Vergot for sending in this video to be shared.

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If you enjoyed this video, you might want to check out the featured videos from previous weeks:  Friday Features

If you come across an interesting or humorous video, or a new product innovation related to agriculture, please send in a link, so we can share it with our readers. Send video links to:  Doug Mayo

 

Pest Identification is Essential and Sometimes Surprising

Pest Identification is Essential and Sometimes Surprising

Throughout my 22 year history as an Extension Agent, I have been the first responder for all sorts of strange things farmers, ranchers, and landowners encounter.  This is one of the critical roles county agents play all over the country.  If you see something odd or unusual, whether it is a new weed, insect or disease, your county agent should be one of the first people you contact to get information.  It is very possible that if you find something you have never seen before, others may not have not seen it either.  County agents are connected to a vast network of experts and identification labs that can help figure out what those strange new things are. Because of the ports, huge numbers of visitors, and tropical storms, new pests and diseases show up in Florida on a regular basis.  It is very important to have new pests identified, before they have the opportunity to spread.

Most of the time the plants, bugs, and diseases agents have identified by experts are harmful in some way to the crops we grow.  Whether it is toxic weeds in pastures, insects feeding on plants, or diseases in crops, the first thing you need to know is, “What is it?” Once the issue is identified, most of the time there are some type of control options available.  Sometimes, however, things are not at all what you expect.  Such was the case this summer as four types of plant pests were identified that turned out to be harmless, and in some cases were actually beneficial.

Specimen #1

Aschersonia aleyrodis on Satsuma is a fungus that feeds on whitefly nymphs. Photo credit: Doug Mayo, UF/IFAS

A citrus grower thought that his satsuma trees were under serious attack.  White flies were already an issue as noted by the sooty mold growing on the leaves, and then this terrible scale that he had never seen was all over the undersides of the leaves of the trees.  While from a distance this looks much like a harmful scale insect, it turned out to be a beneficial fungus that destroys whitefly nymphs!

Dr. Xavier Martini, UF/IFAS Entomologist in Quincy shared the following information:

What you have is not scale, it is citrus whitefly nymphs that have been attacked by an entomopathogenic fungi called Aschersonia aleyrodis. It is very good to have this fungus, because it helps control the whitefly population.

You can read about this in the Featured Creature article entitled: Citrus WhiteflyScroll down to the section called: Parasitic fungi for more details.

Aschersonia aleyrodis fungus on the underside of a satsuma leaf looks terrible, but it was actually making a bad situation better by reducing the whitefly population on young satsuma trees. Photo credit: Doug Mayo, UF/IFAS.

Specimen #2

The beneficial fungus Beauveria bassiana is a natural enemy of kudzu bugs on soybeans. Photo credit: Doug Mayo, UF/IFAS.

A soybean grower saw something he had never noticed before.  A white mold was growing in spots all over the stems of soybean plants in a field.  This is where you have to be careful.  Soybeans can get white mold, which is caused by the fungus Sclerotinia sclerotiorum.  If you do a google search for Soybean white mold, you will find pictures that look somewhat similar.  Upon closer inspection, at the NFREC Plant Pathology Lab, in Quincy,  the fungus was actually Beauveria bassiana which is a biological control of kudzu bugs.  The white spots in the photos are actually dead or dying kudzu bugs, and the fungus was growing on the insects, not the soybean stalks.  You can read more about this beneficial fungus at: Kudzu bugs’ decline is attributed to two factors.

The white spots are beneficial fungus Beauveria bassiana that are attacking kudzu bugs not the soybean stalks. Photo credit: Doug Mayo, UF/IFAS

Specimen #3

Slime mold found growing on a centipede lawn. Photo credit: Doug Mayo, UF/IFAS

A landowner noticed this really strange growth on her centipede lawn.  It looks hideous and destructive.  In truth, it was a relatively harmless plasmodial slime mold, named Fuligo septica.

Larry Williams, UF/IFAS Okaloosa Horticulture Agent shared the following information:

Slime molds mostly function as saprophytes, feeding on and breaking down organic matter. It should not cause any permanent problems or major damage to the lawn. One such slime mold is commonly referred to as “dog vomit” slime mold.

Here is a link to an article on slime molds that pop up on lawns, in mulch, and damp areas under trees with high organic matter: Those Mysterious Molds

Slime mold growing on the moist organic matter in a Jackson County Lawn. Photo credit: Doug Mayo, UF/IFAS.

Oklahoma State University’s diagnostic labs had gotten so may calls from concerned homeowners that they developed a YouTube video on slime molds:

Specimen 4

Harmless slime mold growing on centipede lawn after multiple rainy days. Photo credit: Doug Mayo

A similar scenario was seen on a centipede lawn at a county building in Jackson County.  This slime mold is commonly found on lawns and pasture grasses during extended rainy periods in Florida. While it looks like a serious disease, it is really just another plasmodium species that feeds on decaying organic matter.  As with the large slime mold in specimen 3, what you are seeing is actually the spore masses that will generate more slime molds when conditions are favorable again for growth.  You can knock these off with a garden hose, if you want to, but they disappear almost as fast as they form.  No real harm is done to the grass that is just serving as a platform for slime mold reproduction.

Read more about it in this article written by Matt Orwatt, UF/IFAS Washington Horticulture Agent: Frequent Rains Induce Slime Mold in Panhandle Lawns

Summary

Most of the time, when you see something that does not look normal it is a bad thing, such as weeds, fungal diseases, or damaging insects. But before you spend money on a control, it is really important to have a positive identification of the pest.  Not everything unusual is harmful.  Modern pesticides have become very target specific, so it is vital to first find out what this new thing is before you spend money trying to control it.  So the next time you see something alarming or strange in your crop, pasture, or landscape, contact your local county agent, so you can find out for certain what you are dealing with, and get some science-based advice on a plan of action, if one is needed.