Trap Plants

Leaf-footed bug on giant sunflower

We discovered more bugs in the garden on Wednesday and learned something  about trap plants.  Extension agents Trevor Hylton, Mark Tancig and Horticultural Assistant Kelly Thomas joined us in the garden.  We identified and removed a few Army Worms and Leaf Footed Bugs from various vegetables.  The infestation was light for this time of year, particularly after the mild winter we experienced.  One reason may be trap plants.

Laurie has planted giant sunflowers around the garden, and we have left some other plants that appeared attractive to bugs as evidenced by their leaves.  We have a Pokeweed in the perennial area that looks like lace.  No other plant in the garden has been so well-liked by munching pests.  We haven't identified the culprits yet, but we are happy to furnish them an alternate menu.

Bug-eaten pokeweed
 

We removed army worms from several plants including one that was feasting on a young eggplant.  Army worms are the larvae of a grayish brown moth which sometimes has distinctive spots on it's wings.  The most common are the Fall Army Worm (which is evident in all seasons), and the Southern Army Worm.  They eat plant leaves and bore into fruit.  The greenish or light-colored eggs are laid in clusters on the underside of leaves.  A layer of scales is deposited among and over the eggs giving them a fuzzy or moldy appearance.  Bt, Horticultural oil sprays and Neem oil are somewhat effective as well as hand picking where practical.    Natural predators are birds and other insects, including a number of wasps.  See more about army worms at http://edis.ifas.ufl.edu/topic_armyworms

Army worm on eggplant

Hole where Army worm was removed

Our best discovery was multiple leaf-footed bugs and their nymphs on our first giant sunflower bloom.  We only found a few of the adults on our other plants, but the sunflower was bug city.  We thought about killing them with insecticide, but not many work on leaf-footed bugs, and there was concern about the bees which frequent our garden.  Then Mark asked if we had tried shaking them off.  Well that was just too simple.

 

We added a couple of tablespoons of dishwashing liquid to a few inches of water in a bucket, held the flower head over the bucket, tapped it vigorously, and bugs and nymphs fell into the soapy water, never to plague us again.  We're sure there are plenty others lurking in the vegetable plants, but we interrupted the life cycle of those we found.  See more about leaf-footed bugs in our previous post. 

Nymphs of leaf-footed bugs on Giant Sunflower



Pest Alert - Some Bad Bugs in the VegHeadz Garden

Squash vine borer moth
 

Leon County UF/IFAS Extension Horticultural Assistant Kelly Thomas makes a tour through the vegetable garden most mornings.  This week she noted several "bad" bugs on plants and captured these photos.. 

The  squash vine borer moth is the guy responsible for the sudden collapse of seemingly healthy squash plants.  It lays its eggs on the base of the squash stem.  When they hatch, the larvae bore into the vine and feed there which eventually leads to the collapse of the plant as pathways for water and nutrients are severed by the larvae.  The borer hole can be seen, often with a little pile of frass (bug excrement and plant material) beside it.  Sometimes cutting a slit in the vine and removing the maggot will save the plant if detected early.  Wrapping tinfoil around the base of unaffected squash stems may prevent the borers from entering the stem.  Capturing and killing the moth is a preventive measure, but that is difficult.  However, they fly during the day unlike most moths which fly at night.  The moth resembles a wasp in flight.  They overwinter in the soil, emerging in the spring.  . 

Citrus flatid leaf hopper

The leafhopper or plant hopper at right is also a pest, but it doesn’t do much damage. Kelly found it on an eggplant.  It eats sap from the stem and produces honeydew that ants and bees feed on. The white material produced by the nymphs is sometimes mistaken for mealybugs.  The adults resemble a small white moth, and the nymphs are white also.  They can also be found on citrus and other woody trees and shrubs.  They may be prey for predator wasps. 








The real bad boys are the Leaf-footed bugs shown below.  Kelly says they are breeding like crazy in our garden. They come from a large family of sap-sucking bugs.  They get their name from the leaf-like enlargements or flaps on their hind legs.  They are closely related to stink bugs which are also sap-suckers.  They feed mostly on seeds of tomatoes and other plants such as pomegranates.   Their eggs are brown and cylindrical and laid in a string on a plant leaf or stem.  They should be located and destroyed when possible.    The adults live a relatively long life and lay eggs over a protracted period,  Major outbreaks occur after mild winters, and their population also depends on the amount of natural predators, weather, and food available.   They have piercing and sucking mouth parts which they use to probe into a tomato looking for seeds.  When they find one, they excrete an enzyme which liquifies the seed which they then suck out.  Their damage may destroy small tomatoes, but on larger ones, it leaves a small depression or discoloration in the fruit which does not affect its edibility.  They can be captured and drowned in soapy water.  They can be vacuumed with a hand vacuum.  Shaking the plant can sometimes dislodge nymphs which can be destroyed when they fall to the ground (lay down some paper or something light first so you can see them), but the adults will fly away.  Their predators include birds, spiders, some predator wasps, and tachinid flies.  Application of pyrethrins or other insecticides is problematic as the bugs usually appear when fruit is near harvest.  In addition, any insecticides which may be effective also kill beneficial insects which prey on these bugs and other pests. 


 

See the Pest Control Solutions chart from Native Nurseries . 

Leaf-footed bug

Bug ID - Good or Bad?

I had seen clusters of these insect eggs on kale and other plants in my garden a number of times this spring.  The first time I pinched them reflexively, then tried to determine what they were without success , the second time I left them alone, thinking they might be something helpful.  The third time, there was a huge cluster of them, and I took them to the Leon County UF/IFAS Extension office where Horticultural agent Mark Tancig and his assistant Kelly Thomas solved the mystery.

They are indeed good bugs, and they are not eggs at all.  If you look close, you can see they are a little fuzzy.  They are the cocoons of a parasitoid braconid wasp which preys on the cabbage butterfly.  The cabbage butterfly larvae feed on the cabbage, and the wasps, which can be as small as 1/8" lay their eggs on or in the butterfly larvae.  The eggs hatch and eat the cabbage worm from the inside,  emerging after killing the host caterpillar and then spin this cocoon, eventually emerging from the cocoon  as a new wasp to repeat the cycle.  You will see a little black spot or hole in the end of the cocoon when the wasp has emerged.

There are over  15,000 species of braconid wasps identified worldwide with over 2000 in the US, and many more which are unidentified, maybe as many as 50,000 species.  It's mind boggling.  Braconid wasps also prey on other insects, including aphids and some beetles.  As adults they are pollinators, feeding on nectar and pollen.

For more information about these non-stinging little helpers and how to attract them, refer to an article in Mother Earth News along with some university links furnished there.