Whiteflies-Pest Diagnostic Clinic (left), Whiteflies-Clemson University (right)

Description:
There are several different species including greenhouse whiteflies, silverleaf whiteflies and sweetpotato whiteflies. They occur worldwide and move onto other crops and plants when their food source runs low. They go from egg to larvae to adult very rapidly.

Whitefly Life Cycle-Dept. of Entomology NCSU (left), Whitfly Eggs-Oregan State University

Whitefly damage-College of Agricultural and Human Resources (left), Whitefly damage-Top Turf Insect Damage (right)

Diet and Damage
Host plants include strawberries, house plants, greenhouse plants, vegetables and some ornamentals. Whiteflies are sucking insects and excrete honeydew which can cause a secondary problem…..sooty mold. They cause plants to become weak and plants die from lack of photosynthesis once sooty mold sets in. They are very difficult to control and over the years have developed immunity from some inorganic pesticides.

Biological Controls

1. Plant Guardian^TM Houseplant Insecticidal Soap – use on the underside of leaves as this is where you’ll find them.
2. Pyola^® Insect Spray
   – a plant based organic pesticide that comes in a liquid or powder. The liquid type needs to be diluted with water and then sprayed directly on the affected plants. It also kills a wide range of insects, caterpillars and beetles.
3. Pot Stickers – you can buy these or make your own with bright yellow card coated with a sticky substance like tanglefoot.
4. Rubbing Alcohol – dilute alcohol in water and wipe the undersides of the leaves.
5. Beneficial Insects - ladybugs, lacewings, pirate bugs, spiders and tiny parasitic wasps.
6. Your Trusty Vaccuum Cleaner – they can be sucked off your houseplants with it.

Oil-Away™ Supreme Insecticidal Spray from Gardens Alive is made from cottonseed oil that’s extracted the old-fashioned way, by squeezing or pressing. No chemical solvents, normally used in the commercial extraction process, are used. Unlike some dormant oil products, this one won’t burn or harm sensitive foliage if used in warmer weather. IMPORTANT: It’s best used in the fall after leaf drop or in the spring before leaves or blossoms and beneficial bugs appear. Ladybugs and other beneficial insects that migrate onto a plant after it’s been sprayed are not affected.

You can also make your own dormant oil spray:

1 gallon of mineral oil
1 pound of oil based soap (granular form)
1/2 gallon of water
Boil all these and mix well. Dilution rate 1 part to 20 parts water. This home-made dormant oil must be used immediately (cooled of course) as these ingredients separate quickly.

Chrysanthemum cinerarifolium (Pyrethrum)-NCSU Horticultural Science

Leaf Miner Grub (left)-Bradley Hydroponics, Leaf Miner Larvae (right)-Virginia Cooperative Extension

Description
The adult is a small fly (most having a yellow spot on their back) that lays it’s eggs on the leaves and when they hatch, grubs work inside leaves eating the centres out. There are several different species. Each species named for the plant they attack….ie: Lilac leafminers, azalea leafminers, spinach leafminers, boxwood leafminers etc.

Adult fly-P. Parrella, University of California

Habitat and Lifecycle
Found everywhere in North America. Flies occur in early summer and lay eggs in holes that they pierce in leaves. Eggs hatch within 4 days and begin feeding. When they have completed feeding they drop to the ground and pupate. They overwinter in this stage.

Damage (top left)-Virginia Cooperative, Damage and larvae (top right)-Virginia Cooperative, Damage (bottom)-USDA, John A. Byers

Diet and Damage
They feed on beets, beans, tomatoes, swiss chard, spinach, celery, lilacs, most flowers and boxwood varieties. They have been known to feed on other delicate leafy veggies and some ornamental like azaleas. They cause unsightly yellowish blisters on the leaves of host plants in a very erractic many (they look like trails). There can be as many as half a dozen present per leaf in serious infestations. Fortunately these guys rarely do much damage unless….it’s your spinach or chard. This year I am experiencing an influx of these guys and they seem to be eating everything so perhaps this is a bad year for them.

Control
1) Pyola^® Insect Spray – a plant based organic pesticide that comes in a liquid or powder. The liquid type needs to be diluted with water and then sprayed directly on the affected plants. It also kills a wide range of insects, caterpillars and beetles. Spray insecticidal soap when you see the flies on leaves of plants. I’m not sure it works on the larvae inside the leaves but you never know.
2) Sticky Traps – you can buy these or make your own with bright yellow card coated with a sticky substance like tanglefoot. Put up sticky traps near plants where the flies appear or plants that have been attacked.
3) Till Around Susceptible Plants – If you till the areas where you have them you will uncover the larva and birds will greedily eat them or you can pick them up and drop in soapy water.
4) Parasitic Wasps – Hymenopterous (wasp) parasites are natural predators.
5) Plan Your Harvest – Harvest beets and other veggies earlier then you normally would to decrease loss of veggies and plant in different stages.
6) Hand Pick – If you see the trails, you can crush them between thumb and forefinger. Or you can remove the affected leaves and drop them in soapy water or burn.
7) Row CoversProtect you crops with row covers before the flies emerge.

Bt (Bacillus thuringiensis)

Institute of Cell and Molecular Biology, The University of Edinburgh

Bt is usually found in garden supply stores as a liquid Bt spray Bt does not last long so in many instances it must be reapplied. It can take up to 3 days to kill an insect after it has ingested it but in the meantime they stop feeding on your precious plants, roots and turf. It does not harm earthworms.

Plant Guardian™ Houseplant Insecticidal Soap from Gardens Alive can be used indoors or outside, is all-natural, environmentally friendly and safe for use around kids and pets. It works great on roses, vegetables, fruit and nut trees, strawberries, raspberries, and ornamental and shade trees as well as houseplants. You can apply it to fruit and vegetables up to the day of harvest.

Here is my homemade recipe that you can make at home:
1 or 2 tablespoons of any dish soap to one quart of water. Spray directly on the bugs.

Click here for all natural pesticides from Gardens Alive! I have also listed some organic controls below that you may want to try that can help you alleviate your garden pest problems and still “Go Green”.