Garden Talk

with Rebecca Jordi


Leave a comment

Q: What kind of roaches are these?

 

German cockroach

German cockroach

A:   The bad kind – German cockroaches, Blattella germanica. While none of us like to have cockroaches in our house, the German cockroach is a true pest and the kind of insect that gives all insects a bad name.  It can be found in most any type of building throughout Florida especially multifamily dwellings (apartments). In Florida, the German cockroach may be confused with the Asian cockroach, Blattella asahinai Mizukubo. While these cockroaches are very similar, there are some differences that a practiced eye can discern. The German cockroach is found throughout the world in association with humans. They are unable to survive in locations away from humans or human activity. The major factor limiting German cockroach survival appears to be cold temperatures. Studies have shown that German cockroaches were unable to colonize inactive ships during cool temperatures and could not survive in homes without central heating in northern climates. The availability of water, food, and harborage also govern the ability of German cockroaches to establish populations, and limit growth. Insecticides in the organophosphorous, carbamate, pyrethroid, amidinohydrazone, insect growth regulator, inorganic, microbial, and botanical classes are available for controlling German cockroaches. Insecticide treatments are available in a wide variety of formulations including baits, sprays (emulsifiable concentrates, wettable powders, microencapsulated), dusts, and powders. Non-toxic and low toxic alternatives for German cockroach control are available. Sticky traps can be used to monitor or reduce population size. Improving sanitation by eliminating food and water sources and clutter can have a significant impact on reducing the chances of infestation population size. Finally, exclusion practices such as sealing cracks and crevices will reduce harborage space and also negatively impact population size. For more complete information, consider reading the University of Florida publication titled, “The German Cockroach.”  http://edis.ifas.ufl.edu/in028

Advertisements


Leave a comment

Q: What is this large wasp?

 

Giant_cicada_killer

Giant_cicada_killer

A:  You brought in a Giant Cicada killer or giant ground hornet, Sphecious speciosus, which is the common Florida species. This insect can grow to almost 2 inches long and easily one of the largest wasps found in Florida.  The females of the common Florida species hunt Tibicen spp. cicadas and can dig four-foot burrows in the ground with several branches and cells.  Between one and four cicadas are deposited per cell depending on the size of the adult cicada. Cicada killers are usually considered beneficial insects since they destroy plant-feeding cicadas. Also, they rarely sting except when the females are handled. However, under certain circumstances, such as when elderly persons or young children are present in the breeding areas, one may want to discourage their presence. This can be done by eliminating or reducing the breeding area, which usually consists of exposed, sandy soil. This area can be mulched or covered with grass. Labeled insecticides can be applied to the nesting sites to kill the wasps. http://edis.ifas.ufl.edu/in573


Leave a comment

Q: Formosan termites have been in the news lately – what can you tell me about them?

 

Formosan subterranean termite

Formosan subterranean termite

A:  The Formosan subterranean termite, Coptotermes formosanus, is the most widely distributed and most economically important of the termite species. The Formosan subterranean termite (FST) acquired its name because it was first described in Taiwan in the early 1900s, but Coptotermes formosanus is probably endemic to southern China. This destructive species was apparently transported to Japan prior to the 1600s and to Hawaii in the late 1800s.  By the 1950s, it was reported in South Africa. During the 1960s, it was found in Texas, Louisiana, and South Carolina. In 1980, a well-established colony was thriving in a condominium in Hallandale, Florida. Just recently, they have been identified in Duval County. A single colony of FST may contain several million termites (versus several hundred thousand termites for native subterranean termite species) which can forage up to 300 feet in soil. Because of its population size and foraging range, the presence of FST colonies poses serious threats to nearby structures. The scariest part – once established, FST has never been eradicated from an area. There are more soldiers (10 to 15%) in an FST colony than the native subterranean species in Florida which generally contain only 1 to 2% of the total colony. Because the FST colony contains a larger soldier proportion than native subterranean termites, infestations with many soldiers is a clue to its presence. The FST attacks structural lumbers and living plants because they are sources of cellulose. However, this termite is also known to attack non-cellulose materials such as plaster, plastic, asphalt, and thin sheets of soft metal (lead or copper) in search of food and moisture. Their highly publicized ability to penetrate solid concrete is a fallacy. However, the FST is persistent in finding small cracks in concrete, which they enlarge and use as foraging routes. Leaky plumbing, air conditioning condensate, and any portion of the building collecting excessive amounts of moisture should be corrected to maintain an environment less attractive to FST. The conventional method for control of subterranean termites, including the FST is to place a chemical barrier between termites and the structure to be protected. In recent years, baits have become available to control Formosan subterranean termite populations near a structure. When termites are found in the station, the monitoring device is replaced with a tube containing chitin synthesis inhibitor (CSI) laced bait with the active ingredient hexaflumuron. Termites feeding in the stations then carry baits to other members of a colony, leading to the demise of entire colony population.  For more complete information, please read the following University of Florida publication:  http://edis.ifas.ufl.edu/in278


Leave a comment

Q: Can you identify this caterpillar? I found it under my redbud tree.

Tolype velleda larva

Tolype velleda larva

Tolype velleda moth

Tolype velleda moth

A:  I have not seen this large caterpillar before, so I called an entomologist at the University of Florida who identified it as the caterpillar of the Large Tolype moth.  The two – three inch caterpillar can be found feeding on the leaves of apple, ash, birch, elm, oak, plum, and several other trees.  The first thing you will notice about the Large Tolype adult moth is the white to grey hairy body. The moth grows from 1 – 2.5 inches long. The Large Tolype moth is a very striking moth with variations of color from white to black and grey – love to have one in my collection.  The Large Tolype moth can commonly be found from as far north as Nova Scotia south to central Florida, and westward to Minnesota, Nebraska, and Texas.


Leave a comment

Q: The buds of my hibiscus are turning yellow and dropping off. What is wrong?

Hibiscus bud midge maggot

Hibiscus bud midge maggot

A:  After opening one of the yellowing buds we discovered the hibiscus bud midge maggot, Contarinia maculipennis.  The female midge deposits eggs on the tips of the newly forming buds and within 24 hours the maggot develops and starts to feed on the bud.  It takes about one week for the insect to mature to the next stage; then they drop to the ground to pupate. The soil must be moist, which is generally not a problem in our landscapes.  It will take about 2 -3 weeks to mature into an adult. The adult midge is very small – similar to a mosquito. Although hibiscus is the favorite, the bud midge has been known to also infest tomatoes, jasmine, plumeria, other vegetables and ornamentals. There are other reasons for flower buds to turn yellow and drop off such as over watering, too much nitrogen, thrips or aphids, and very hot, dry weather.  However, since I found the maggot, I am going to blame it on the bud midge.  The best thing for homeowners to do is to be sure to clean up any buds and leaf litter which have dropped to the ground.  If the hibiscus plants are in the ground they may not need supplemental watering aside from what we get with rain.  Remember, the midge requires moist soil to pupate.  Contact chemical sprays don’t work well since they cannot penetrate the bud.


Leave a comment

Q: What is the name of the insect and what does it do? It looks like it has a long stinger at the end of the abdomen.

Broadnecked Root Borer

Broadnecked Root Borer

A: I believe the insect you brought in to the office is a Broad-neck root borer, possibly Prionus laticollis.  The female is much larger than the male, growing to two inches or more. The structure you see at the end of the abdomen is actually called an ovipositor, not a stinger. Ovipositors are structures on female insects in which they deposit eggs. This particular insect deposits eggs into the ground around trees and shrubs. The yellow eggs are about 1/8 inch long developing into larvae which then feed on the living roots of trees and shrubs. One female may lay as many as 100 eggs in clusters. The larvae may be as long as 3 ½ inches with black mandibles (very scary).  Broad-neck root borers prefer deciduous trees of the forest but have been known to feed on fruit trees and shrubs such as peach, pear, apple, blueberries and even grapes. The complete life cycle takes about three years. Adults emerge from the ground between June and August eating the foliage of trees and, on some occasions, even damaging the fruit.  Generally, the adults feed at night but stay hidden during the day. The smaller males are seen more often as they are attracted to light. Broad-necked root borer’s range is from Quebec and Ontario to Minnesota and as far south as Florida.  Because the larva of this insect feeds exclusively on the roots of trees, the only visible symptoms are limb die-back and the yellowing and/or thinning of foliage. Borers can completely destroy young trees and make older trees more susceptible to being blown over.  Prevention is the best way to deal with a borer. Keep grass, leaves, mulch, bark and other litter cleared away from the bases of trees. This prevents the borer from having a place to hide and makes it more visible to predatory birds. In addition, avoid over pruning, over fertilizing and over watering trees – all of these can cause additional stresses. 


Leave a comment

Q: What is this caterpillar eating my parsley?

Black Swallowtail caterpillar

Black Swallowtail caterpillar

A:   Thank you for sharing the photo. This is the larvae or caterpillar of the Black Swallowtail butterfly.  The black swallowtail larvae are often confused with the monarch butterfly caterpillar as the colors are quite similar. However, if you look closer you will notice distinctive differences in the yellow and black markings of the two caterpillars. On the black swallowtail caterpillar, the yellow coloring breaks up the black whereas on the monarch the yellow and black seem to form more straight bands. Once you see them side by side you will never make the mistake of confusing them.  It is interesting how different both of the caterpillars look from the adult butterfly.  You would think the adult butterfly would at least keep the same color as the caterpillar – yellow, black and green.  However, the monarch butterfly develops into an orange and black butterfly while the black swallowtail is almost completely black.  Nature never ceases to amaze me.

Monarch Caterpillar

A:   Thank you for sharing the photo. This is the larvae or caterpillar of the Black Swallowtail butterfly.  The black swallowtail larvae are often confused with the monarch butterfly caterpillar as the colors are quite similar. However, if you look closer you will notice distinctive differences in the yellow and black markings of the two caterpillars. On the black swallowtail caterpillar, the yellow coloring breaks up the black whereas on the monarch the yellow and black seem to form more straight bands. Once you see them side by side you will never make the mistake of confusing them.  It is interesting how different both of the caterpillars look from the adult butterfly.  You would think the adult butterfly would at least keep the same color as the caterpillar – yellow, black and green.  However, the monarch butterfly develops into an orange and black butterfly while the black swallowtail is almost completely black.  Nature never ceases to amaze me.