Mole Crickets

Mole Crickets

A mole cricket has a face only a mother could love. They are so strange looking, in fact, that in the past week I’ve had two people ask me what they were. They have large, round, helmet-like heads, undersized eyes, and massive front claws used for digging. Unlike your garden-variety crickets, which really don’t cause any major damage to home landscapes, the mole cricket is quite the turfgrass menace. Instead of hopping about aboveground, they tunnel beneath the lawn and feast on the roots and leaves of grass, often destroying entire yards. They are also vegetable pests, going after tomatoes, cabbage, and peppers.

A young mole cricket. Its round head and large front claws distinguish it from other cricket species. Photo credit: Lucy Adams Stevenson
A) Horizontal and B) vertical view of a generalized tawny mole cricket burrow showing
1) horn, 2) 1st constriction, 3) bulb, 4) 2nd constriction, 5) turn-around,
6) surface tunnel, and 7) deep tunnel. Figure 1 from Nickerson et al. 1979. Ann. Entomol. Soc. Am. 72(3):438-440.

Mole crickets spend most of their time below ground and form burrows for hiding, laying eggs, and traversing through their territory. In mating season, males create a monotone song that averages 88 decibels—as loud as a motorcycle! The call comes from their burrows, which have funnel-like openings that expand at the surface, creating amplification comparable to a horn.

Beneficial larra wasp parasitizing a tawny mole cricket. Photo credit: UF IFAS

The tawny mole cricket (Neoscapteriscus vicinus) is the most common to our area and is an invasive species from South America. UF IFAS has had a specific research program related to mole cricket management since the late 1970’s. One successful outcome of this program has been the introduction of a biological control species, the larra wasp (Larra bicolor). The wasp manages mole cricket populations by stinging and temporarily paralyzing crickets. A female will then deposit an egg into the mole cricket’s body. The cricket recovers and goes about its daily routine until the egg hatches, at which point the larval wasp feeds on and eventually kills the mole cricket. Along with the wasp and release of flies and a nematode that also manage mole crickets, the biocontrol methods introduced between the 1980’s and 2004 have resulted in a 95% reduction in mole cricket populations in north Florida.

If you are seeing mole crickets, you can attract larra wasps to your property by planting shrubby false buttonweed or partridge pea plants, which the wasps feed on. If you have serious damage from mole crickets, check out this thorough Mole Cricket Integrated Pest Management Guide, or contact the horticulture agent at your local county extension office to get a site-specific recommendation for management.

Japanese beetle – Be Aware of the Potential Threat, Stay Informed.

Japanese beetle – Be Aware of the Potential Threat, Stay Informed.

Credit: Worrel Diedrick, Florida A&M University

They are known for their voracious feeding habits, targeting a wide range of plants, including ornamentals, fruit trees, and vegetables. I speak of no other than the Japanese beetle (Popillia japonica) an invasive species in the United States, originating from Japan.  

Though reports have been made of Japanese beetle sightings in Florida, there is still not a known established population. However, it’s important to note that the status of Japanese beetles in Florida can change, potentially rapidly, over time. Thus, it is important to be able to identify the species’ host plants and damaged caused. Early detection, monitoring, and swift action can help minimize the potential damage caused by invasive species like Japanese beetles that could potentially have negative impacts on agricultural crops, gardens, and ornamental plants.

Description

The adult Japanese beetle is an attractive pest that is generally metallic green, with bronze or copper-brown wing covers that do not completely cover the abdomen, revealing five patches of white hairs on each side and one pair on the last abdominal segment. These features distinguish Popillia japonica from all other similar looking beetles. In terms of shape, Japanese beetle generally have a broad oval body structure. Notably, the female beetles tend to be larger in size compared to their male counter parts.

Developmental stages usually take place under the soil after the female deposit her eggs. In most instances they complete their life cycle in one year emerging later in the summer months, however this varies based on locations.

Host plants

Japanese beetles have known to have over 300 host plant species; however, some common host plants include maples, soybean, ornamental apple species, plums, peaches, roses, blackberry, raspberry, limes, elms, grapes, and corn. Crepe myrtle and turfgrasses are also host plants.

Damages

Both adults and larvae cause plant damage. Adults feed on the foliage of host plants resulting in skeletonization of the leaves, while larvae feed on the root systems of turf and pasture species, affecting the ability of the plant to uptake nutrient and water from the soil.

Management

If Japanese beetle populations do become established in Florida, it is generally advisable to take measures to manage the population such as physically removing them, using pheromone traps, or other integrated pest management strategies. Chemical recommendations are not currently available in Florida since this beetle is not reported as a pest problem. However, it is always advisable to contact your Local Extension office for recommendations. The United States Department of Agriculture (USDA) has also provided some useful information on the Japanese beetle in their homeowner’s handbook titled “Managing the Japanese Beetle: A Homeowners Handbook’’.

For the most current and accurate information specific to Japanese beetles in Florida management and species identification, consult your extension office. Supporting document can also be found by clicking the link below.

Useful resources:

How to Manage Citrus Leafminer in Your Backyard

How to Manage Citrus Leafminer in Your Backyard

By Danielle Sprague & Dr. Xavier Martini

Citrus is one of the most cherished fruit trees in the Panhandle. Citrus owners are well aware that every year the main damage to their trees come from citrus leafminer (CLM). CLM is a small moth and its larvae feeds between the tissue layers of new leaf growth, causing serpentine mines to form under the leaf cuticle (Fig. 1). The feeding damage results in leaf curling and distortion, and severe infestations of CLM on young trees can retard the growth of trees. Another threat concerning CLM in Florida is that the mines provide an open wound for citrus canker to enter, a bacterial disease that has been found recently in the Florida Panhandle, Georgia, and Alabama.

Citrus leaf miner adult (picture Lyle Buss). (B) Citrus leaves with citrus leafminer mines (picture: Xavier Martini)

Chemical Control

Most commercial growers deal with CLM in young trees by a soil application of systemic insecticide before the flush season, followed by a foliar insecticide when the systemic drench’s toxicity is declining. Homeowners, however, have limited access to these chemistries. Garden systemic insecticides that include imidacloprid (Bayer’s Tree & Shrub Insect Control™, Merit®, etc.) and dinotefuran (Greenlight Tree and Shrub Insect Control™, Safari®, etc.) are among the few options for CLM control. For the best efficacy, those insecticides should be applied two weeks before the start of the flushing season to allow time for the insecticide to move from the roots into the canopy. To avoid leaching of insecticide away from the root zone, soil applications should be made within a 24-hour period without rain. Citrus trees usually have several flushes per year, depending upon cultivar, climate, and crop load. However, in the Florida Panhandle, most citrus cultivars have two major flushes in May and September.

Importantly, systemic insecticides are only efficient against CLM for small immature trees; therefore, the only products labeled for use against CLM on mature trees are foliar sprays. Horticultural oils or insecticides with spinosad (such as Monterey® Garden Insect Spray) are some options available for homeowners. However, achieving leafminer control with foliar applications on mature trees is challenging due to unsynchronized flushing of trees. Foliar applications should be timed with the appearance of the first visible leaf mines. In any case, be sure to READ THE LABEL and follow all the label directions.

Cultural practices, and non-insecticidal methods.

For isolated trees in a backyard, cultural practices and control through mass trapping are usually sufficient to control CLM and insecticide use is not recommended, especially for mature trees. One of the basic cultural practices is to remove any stems that grow below the bud union or from the rootstock, also called ‘suckers’ (Fig. 2). Those rootstock shoots compete with the scion shoots and are great reservoirs for CLM; removing them will help reducing CLM population. On isolated trees, mass trapping using CLM pheromone provide good results (Fig. 3). The mass trapping method is constituted of a delta trap baited with a lure that emits a large quantity of CLM sex pheromone. CLM males are attracted by the odor and are captured in the delta trap’s sticky liner. Those traps are commonly used by growers to monitor CLM populations, but for homeowners they are sufficient to control CLM on a single tree. This trap and a lure method should protect a single tree for approximately 3 months. Finally, the last option is the use of biological control.  Several natural enemies are predators or parasitize CLM. In some case, biological control can reduce CLM populations by 90%. Primary predators of CLM include ants, lacewings, and spiders, as well as a parasitic wasp, Ageniaspis citricola that was introduced into Florida and has become established (Fig. 4).

New growth from the rootstock (called ‘suckers’, red arrow) are a source for CLM infestation and should be removed.
Baited pheromone trap for citrus leafminer (picture Danielle Sprague).
Citrus leafminer serpentine mine parasitized with Ageniaspis citricola larvae (picture Lyle Buss).

Going bats for insect control

Going bats for insect control

The Case for Bats

Biological control is a pillar of integrated pest management.  It may seem a bit daunting the principle is simple.  All things in nature have predators including insects.  Biological control is simply building a conducive environment for the predators of undesired pests.  One animal not often thought of in this capacity is bats.  Insectivores by nature, these underutilized creatures have a big impact to your open spaces.  Their steady diet of moths (Lepidoptera), beetles (Coleoptera) and flies (Diptera, which includes mosquitoes) reduce insect pressure to your gardens and landscaping.

I know what you are thinking.  How effective can they possibly be?  Pregnant females consume up to two thirds of their body weight through the summer months while rearing pups.  Bats are small but keep in mind that these are not solitary animals.  In south Texas, a single large colony consumes enough insects to save cotton farmers an estimated $741,000 per year in insecticides.  That is just to illustrate the point as you won’t be able to attract huge colony.  There is no reason to believe a smaller colony will not provide similar services in your gardens.

Habitat

Now that your interest is piqued, how can you attract bats to your property?  Installing a bat house is the easiest way.  They are typically a two foot by one foot structure holding single or multiple chambers in which bats roost.  It provides shelter from predation and weather while providing a place to rear pups.  Though commercially available they may be built at home with minimal cost.  Place the bat house in a location with morning sun at least 12 feet off the ground.  Ensure there is enough airflow around the house to keep them cool, but that the structure is watertight.  Mount houses on poles next to buildings and you’ll have better success attracting residents.  With everything in place, it is time to discover who will most likely be your new neighbor.

bathouse on pole

photo: Joshua Criss

 

The Bats of North Florida

Florida is home to 13 species of bats statewide.  Of these, 11 may be found in the Panhandle but only 3 are common enough to be routinely seen.  The Brazilian free-tailed bat (Tadarida brasiliensis) is the most common.  Medium sized with brown fur, they have a long tail, wrinkled cheeks, and roost in man-made structures.

Brazillian free tail bat

Photo: IFAS

Second most common are Evening bats (Nycticeius humeralis).  These dark brown to yellow bats have short ears with a broad hairless muzzle.  They are tolerant of other bat species often roosting in tandem with them.

Evening bat

Photo: IFAS

Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius).  Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes.  This species is the bat most likely to eat mosquitoes.

Southeastern Myotis

Photo: Jeff Gore, FWC

Finally, the panhandle is home to Southeastern Myotis (Myotis austroriparius).  Easily the smallest of these bats, they are dull gray to brown with a lighter belly and long hairs between their toes.  This species is the bat most likely to eat mosquitoes.

A Word of Caution

No article on wildlife would be complete without a word of caution.  Bats are wild animals and should be treated as such.  Never touch a bat on the ground as it most likely is not healthy.  Bats do not generally cause issues but have been known to be disease vectors.  Call a professional to collect the animal and never bring it into your home.

Bats can be a wonderful tool in controlling pests on your property.  Creating habitat can help reduce pesticide need and cost to the homeowner.  For more information on bats, see this Ask IFAS document, or contact your local extension agent for additional information on this and any topic regarding your gardens and more.

 

Using Clover as a Winter Garden Cover Crop

Using Clover as a Winter Garden Cover Crop

One of the major recent movements in production agriculture has been the widespread adoption of cover crops.  This practice gives farmers a host of benefits, from erosion prevention to nutrient retention and recycling.  However, using cover crops isn’t just for large scale farming operations.  Hobby vegetable gardeners can absolutely employ similar systems on a smaller scale to reap the same benefits.  For the past two years, I’ve used Buckwheat to provide a soil building cover during the heat of summer between spring and fall gardens.  This winter, after my fall greens garden succumbed to frost, I decided to employ the same tactic with a mix of Red Clover (Trifolium pratense), White Clover (Trifolium Repens), and Crimson Clover (Trifolium incarnatum) to enhance my soil during the coldest months until spring tomato planting arrives!

Clover mix used as a cool season cover crop in raised beds. Photo courtesy Daniel Leonard.

While there are many different species of plants (rye, oats, wheat, various brassicas, etc.) that can be planted in November or December as cool season covers to deliver benefits like winter weed suppression, enhance soil organic matter, retain and harvest leftover nutrients, and provide habitat for beneficial insects, I chose Clover for an additional reason.  In addition to the above benefits, Clover is a legume and also fixes atmospheric nitrogen, making it available for subsequent plantings!  Not only is Clover an excellent soil cover, but it also provides some nitrogen fertilizer to the following vegetable garden!

Growing Clover, while not quite as simple as Buckwheat or small grain covers like oats and rye, is relatively easy for most gardeners.  The first step is selecting which clover species and/or variety to grow.  I chose a mix of Crimson, White, and Red Clover simply because I had several pounds of each left over from a previous field planting.  However, any one of the three may be used by themselves or in various combinations.  All are excellent choices for garden cover crops and have similar growing requirements.  Crimson Clover is the most readily available, but all three species can be found at most farm and garden supply stores.

The next step is to prep your garden beds for clover seeding.  I thoroughly remove weeds from my raised beds, lightly till the top couple of inches of soil, and rake to provide a level surface.  Since clover seed is tiny, a smooth, clean seedbed is a must for excellent germination.  Once this is done, your next should determine how much seed to plant.  Recommended clover seeding rates are usually given on a per acre basis and range from 3-4 lbs/acre (White Clover) to 20-25 lbs/acre (Crimson Clover).  Given these seeding rates, planting in a 4’x8’ (32 ft2) raised bed is only going to require a miniscule amount of seed.

Clover mix used as a cool season cover crop in raised beds. Photo courtesy of Daniel Leonard.

To ensure a good stand while minimizing risk of overplanting, I mix equal parts clover seed and either sand, vermiculite, or other media similar in size to clover seed and hand scatter over the surface of my beds, making sure to uniformly cover the entire bed.  If you think the stand is too thick, you can always hand-thin after emergence.

As a group, clovers prefer moist soil that is not allowed to dry out completely.  This isn’t usually a problem given the Panhandle’s frequent rainy cold fronts in winter, but if rainfall is inconsistent, some irrigation will be required.  Supplemental fertilizer isn’t normally necessary when planting a clover cover in vegetable gardens because nutrients remaining from the previous veggie crops are usually sufficient for growth and development (N especially is not needed as legumes produce their own through N fixation).  2-3 weeks before you’re ready to plant your spring veggies, chop the clover cover into the top few inches of your bed to terminate it and release its nutrients back into the garden.  It’s that easy!

Planting a winter legume cover crop like clover is a great way to harness the benefits of cover crops for your spring veggies and enhance the aesthetics of your otherwise barren and drab garden beds!  For more information about growing winter cover crops or any other horticultural topic, contact your local UF/IFAS County Extension office.  Happy Gardening!