Love Bugs

Adult Love Bugs

We seem to be currently having our semi-annual infestation of love bugs. These little pests are actually flies in the family Bibionidae. They were reported in Louisiana in the 1920’s and by the 1940’s had invaded Florida. It was erroneously reported that love bugs were introduced into Florida by the UF and USDA entomologists. However, love bugs were well established in Florida before any research was conducted. There is clear documentation on the movement of this pest around the Gulf Coast and into Florida.  This fly was first collected in Escambia County, the western most county in Florida, in 1949. It has now spread all over the state.

Love Bug Larvae

Two flights occur each year. The spring flight occurs in late April and May and the second flight occurs in August and September. Flights extend over periods of 4-5 weeks. Mating takes place almost immediately after the emergence of females. Adult females live only 2-3 days and feed on nectar of various plants. Love bugs are attracted to irradiated exhaust fumes (gas and diesel fumes exposed to sunlight) at temperatures above 83 degrees F. (usually between 10:00 a.m. and 4:00 p.m.). Also, hot engines and the vibration of vehicles apparently contribute to the attraction of love bugs to highways.

Females may lay as many as 350 eggs which are usually deposited on decaying plant material. Larvae feed on the decaying plant material and live on the soil surface just beneath the decaying organic matter. The larvae are often found in pastures under cow manure. They perform a beneficial function, because they convert plant material into organic components which can be used by growing plants.

There isn’t any practical way to control love bugs with insecticides in large areas. However, smaller areas around a home could be sprayed with a registered insecticide. Love bug numbers have been somewhat reduced in recent years by predators such as birds and armadillos, and invertebrate organisms such as earwigs, beetle larvae and centipedes. There are a number of fungi which also can appreciably reduce larvae numbers. In spite of all of the natural controls, they still are a real nuisance.

There are several options available to lessen the problems facing motorists. By traveling at night motorists can avoid love bugs as they do not become active until mid-morning. Screens can be placed in front of the radiator to block incoming adults. Also, deflector shields placed at the front of the hood help reduce the number of adults impacting on the windshield and upper front finish.

Splattered bugs should be washed off the car as soon as possible. Love bugs are more easily removed, and the chance of damaging the finish on the car is lessened, if the car has been waxed recently. When the remains are left on the car for several days, the finish will often be permanently damaged. This is because the bodily contents of love bugs is somewhat acid and the acidity will increase through bacterial action over a period of a few days. Auto paint has been improved over recent years which has lessened this problem. Soaking the area for several minutes will ease removal. When love bugs are numerous, some motorists spread a thin layer of baby oil over the front of the hood, above the windshield and on the grill and bumper. This practice will make removal a simpler task.

 

 

 

 

Sawflies - What Are They?

Recently, a homeowner reported what appeared to be an insect infestation on a tree at her home in southwest Lakeland.  She indicated that this infestation had occurred for the last 7-8 years in March and the tree was usually defoliated. I thought oak tree caterpillars, but the homeowner said definitely not an oak. She further indicated that the larvae were everywhere - on the tree, falling out of the tree to the ground and in her hair, crawling up the house, on trash cans, and on her other landscape plants. This all seemed very unusual and required investigation!

Blackheaded Ash Sawfly Larvae

I visited the homeowner and saw the tree and the infestation – the tree was pretty much white with these caterpillar-like creatures. I thought this insect was a sawfly, but didn’t know which one and could not identify the tree. With the help of the Forest Service and the UF Department of Entomology, the tree was identified as a white ash (not common in Polk County) and the bug as a blackheaded ash sawfly. I had not seen the bug or the tree in Polk County before. This huge infestation had been occurring on this single homeowner tree for the past seven years. Apparently this white ash was able to withstand the repeated injury.



Infested White Ash Tree

So, what are sawflies? They are not flies at all, but are a primitive group of insects in the wasp, ant and bee order – Hymenoptera. The adult sawfly looks nothing like adult moths and butterflies as they are wasp-like, often brightly colored, and are usually found on flowers searching for host plants, mates or prey - some adults are predators. The sawfly larvae are quite different from the typical bee or wasp larvae which are grub-like. Sawfly larvae look like moth or butterfly caterpillars at the first glance as they all have leg-like structures on the abdomen called prolegs for locomotion. However, moth and butterfly caterpillars have not more than five pair of abdominal prolegs with crochets (hooks) for grasping while sawflies have six or more pair of prolegs which do not have crochets. So, sawflies are pretty easy to distinguish from moth and butterfly larvae.

Control of this infestation for the homeowner probably will be quite difficult. The tree could be sprayed with a conventional insecticide in March to control the larvae, but this treatment would be quite expensive – probably not an option for the homeowner. A possible treatment in this case is a fall application of a systemic insecticide like Bayer Advanced Tree and Shrub Insect Killer. Making the application in the fall would give the chemical time to translocate into the upper branches and foliage of the tree by spring-time. The larvae hopefully will then die after feeding on the foliage. No guarantee that this systemic treatment will work. Keeping the area under the tree clean may also help reduce adult numbers in the spring and reduce the infestation.  

Blackheaded Sawfly Larvae Clustered on Trunk

 

 

Blackedheaded Sawfly Larvae on Understory Plant

 

 

 

 

 

Citrus Greening - What's a Homeowner To Do?

Citrus Greening is a disease transmitted to all varieties of citrus and some ornamentals (i.e. box orange and orange jasmine) in the Rutaceae family by a little insect called the Asian Citrus Psyllid (ACP). The insect was first found in Florida in 1998 and the disease, which is a bacterium, was discovered in residential trees in south Florida in 2005. The insect and the disease occur in citrus production areas all over the world and now occur in most if not all citrus production areas in the United States and Florida. The disease is present in most commercial groves and probably in most if not all homeowner citrus trees. Commercial growers in Florida are struggling to control this disease. Chemical control of the psyllid and removal of infected trees are the only methods currently available to growers to manage the spread of the disease.

How would a homeowner determine if his tree is infected? Symptoms can be found year round but are most common September through March (see below). The tree may remain symptomless for some time after it has acquired the disease. Symptoms include vein corking, fruit remain green at blossom end, leaves with yellow veins, reduced fruit size, yellow shoots, fruit and leaf drop. Blotchy mottle in leaves is a key early diagnostic symptom. The tree will gradually decline and the juice will become bitter and of no value. The tree will decline over a number of years and may eventually die.

Is there some treatment to help control this disease? There are no specific treatments for control of this disease in the home landscape or in commercial groves. If a homeowner does decide to plant a citrus tree, then it would be best to treat the soil around the tree with a systemic insecticide at planting like Bayer Advanced Citrus, Vegetable and Fruit Insecticide with imidacloprid. This treatment may control the psyllid and prevent greening infection while the tree is relatively small – 8 or 9 feet tall however, this treatment may not be effective for preventing greening infection in large mature trees.

It has been found that very healthy trees in commercial groves are able to live with the disease and be productive for a longer time than unhealthy trees. So we encourage homeowners to closely follow fertilization recommendations and make sure the tree has ample water during periods of low or no rainfall to minimize tree stress. As the greening bacterium blocks off the phloem preventing nutrient transfer to the leaves from the roots, we recommend making 2-3 foliar applications of micronutrients at full leaf expansion during leaf flushes in the spring, summer and late summer/fall. The application of horticultural oils, like Volck Oil, to control sucking insect infestations will also help minimize tree stress.

Are there any on-going non-invasive research projects for control of greening which might have homeowner application? The USDA at Ft. Pierce is currently conducting experiments using heat treatments to kill the greening bacteria in infected trees - this is intended for commercial use at this point? I don't, at the moment, see how this could be done on a commercial scale, but it might have homeowner application. A possible scenario would be to cut the tree back to a few feet off the ground then cover and apply heat to a specific temperature. However, there are many questions to be answered. What kind of tree cover to use and what type of heat source? What temperature is needed and for how long - the temperature would need to be high enough to kill the bacteria and not damage the tree? How often would some type of heat treatment be needed? A greening infected tree has the bacterium in the roots, so how fast would the upper growth be infected from the roots? And what is the potential for re-infection by wild psyllids. The USDA Lab in Ft. Pierce is offering a workshop on April 30th which I plan to attend.    

Until reliable control options become available to homeowners we recommend planting some other type of fruit – there are many to choose from including pomegranate, fig, blueberry, peaches, plums, nectarines, blackberries, and many more.

Adult Asian Citrus Psyllid Feeding on Citrus Tree Leaf

 

Differential Fruit Size

Typical Blotchy Mottle

Color Break - Fruit Green at Blossom End

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Yellow Veins

Yellow Shoots

 

Fertilize Your Lawn Now

If you have not fertilized your turf then now is the time to make the first application of the year. Selecting a fertilizer is the first step. Most of the retail garden centers should have a product which will fit your needs. When you look at the fertilizer bag you will see three large numbers on the front of the bag. The first number stands for percent nitrogen (N), the second stands for the percent phosphorous (P) and the third stands for percent potassium (K). In other words if the product is a 16-2-16 then a 100 pound bag would have 16 pounds of nitrogen, 2 pounds of phosphorous and 16 pounds of potassium. The other 66 pounds consists of some sort of filler like sand. You have probably noticed that the middle number which represents phosphorous is quite low. The reason for this is that most soils in central and north Florida have an ample amount of phosphorous already in the soil. Adding addition phosphorous is usually not necessary and can easily runoff into our waterways encouraging exotic plant growth.

We recommend selecting a turf fertilizer which has nitrogen in a 1:1, 2:1 or a 3:1 ratio with potassium (third number) and 30-50% slow release nitrogen. Acceptable products include Scotts Turf Builder for Southern Lawns (32-0-10) which has 50% slow release nitrogen, and a 3 to 1 nitrogen/potassium ratio; and Lesco 24-2-11 fertilizer which contains at least 50% slow release and has 2:1 nitrogen/potassium ratio. It is important to have no less than a 3:1 nitrogen/potassium ratio as potassium is important for building strong roots which increase turf tolerance to stresses. There are other acceptable products on the market, but space prevents listing any more. And there are more inexpensive products available which have a greater than 3:1 nitrogen/potassium ratio such as one sold locally with a 29-0-4 ratio which we don’t recommend due to low potassium.

You will find stacks of weed and feed products at the retail garden centers right now. We do not recommend weed and feed products because weed killer applications should be made in mid-February to be most effective followed up with a second application before April 15^th. Mid-February would be much too early to apply a turf fertilizer in a weed and feed product since most turfgrass is still somewhat dormant at this time. Fertilizer applied in mid-February has the potential to leach and run off into our waterways during a substantial rain event. The correct time to apply turf fertilizer in central Florida is at the end of March. However herbicides in a weed and feed product applied at this time would be applied too late to control many germinating weeds. So, weed killers should be applied in mid-February with a second application before April 15^th and fertilizer should be applied at the end of March to be most effective and Florida-Friendly.

Let’s say that you have selected the Scotts Turf Builder for Southern Turfgrasses (32-0-10) or the Lesco 24-2-11 for your lawn fertilizer. The next question is how much to apply? The University of Florida and Polk County require that not more than one pound of nitrogen be applied per 1000 square feet of turfgrass per application if the product has 30-50% slow release nitrogen and 1/2 pound nitrogen if the product has less than 30% slow release nitrogen.

You have these bags of formulated fertilizer (32-0-10) and (24-2-11) so how much of the product in this bag equals one pound of nitrogen. This can be calculated by dividing 100 by the percent nitrogen in the bag (32% and 24% nitrogen) – 3.3 pounds of the 32% nitrogen product and 4.2 pounds of the 24% nitrogen product equals one pound of nitrogen.   A 50 pound bag of the 30% nitrogen product will cover about 15,000 square feet of turfgrass  and a 50 pound bag of the 24-2-11 will cover about 12,000 square of turfgrass applied at one pound of nitrogen per 1000 square feet of turf. Applied at 1/2 pound nitrogen the bag would cover twice the square footage - 30,000 and 24,000.

Next you are going to have to determine how many square feet of turfgrass you have in your landscape. Square feet is determined by multiplying width by the length. A tape measure or roll-a-tape would be handy tools to help make this calculation. Let’s say your front turfgrass is an area which is 150 feet long and 35 feet wide. Thirty-five multiplied by 150 equals 5250 square feet of turf area. The correct amount of 30-0-10 product for 5250 square feet calculates out to be 17 pounds based on the product being applied at 3.3 pounds per 1000 square feet. (3.3 pounds 30-0-10 X 5250 square feet turf divided by 1000 square feet =’s 17.3 pounds.)

Next you will need to calibrate the output of your rotary spreader. We have already determined that 3.3 pounds of 32-0-10 fertilizer needs to be applied per 1000 square feet to equal one pound of nitrogen per 1000 square feet. An area smaller than 1000 square feet needs to be selected to practically calibrate the spreader.  Lay out a small area something like 200 square feet, an area 10 feet wide (assuming the spreader throws five feet to each side) and 20 feet long, and cover with plastic. This area would require 1/5 (0.2) of the recommended fertilizer for 1000 square feet or 3.3 pounds divided by 5 which equals 0.66 pounds. Set the spreader output level at a medium opening. Fill the spreader half full with fertilizer and pass over the 200 square foot area. Pour the expended fertilizer from the plastic sheeting into a container and weigh. Adjust opening until 0.66 pounds is expended per pass over the 200 square feet test area. It may be a good idea to calibrate the spreader at 1/2 the above rate and cover the turfgrass twice in different directions to minimize missed areas.