Japanese Beetles are now becoming a problem in our area. See these two publications for more information and control options... Japanese Beetles in the Urban Landscape (ENT-451) Japanese Beetles (ENT-409)

Vegetable Garden questions?...

see HomeVegetable Gardening in Kentucky for helpful information.

Horticulture This Week...

Aphids!
In the past week I have had several homeowners bring in leaves infested with aphids.  People often over look this small insect and instead just notice the damage that the aphids are causing.  Aphids are soft-bodied insects that feed on plant sap and are usually found on the undersides of leaves.  While even heavy infestations of aphids do not spell doom for your tree or plant, it can lead to yellowing, wilting, severely distorted leaves, or leaf drop.  While the damage that I have noticed has only been on shade trees so far this season, aphids also feed on small fruits, vegetables, landscape ornamentals, and fruit trees. 

  Aphids are tiny (only 1/32 to 1/8 of an inch long) pear shaped insects with two short tubes (cornicles) protruding backward from the abdomen.  They come in a variety of colors including green, pink, black, gray, or white.  They may or may not have wings.  Almost all aphids are female and can give birth almost continuously without mating.  Only in the fall are males produced, at which time they mate with females who go on to produce eggs that will overwinter.

  These small insects also secrete a sugary, liquid material out of their cornicles called “honeydew”.  A fungus called sooty mold can grow on the honeydew deposits causing leaves and branches to appear a dark color.  If seen this is a sign of aphid activity.  Also look for a thick powdery appearance on the leaf.  The “powder” is actually aphids and skin casts.

  Try to scout your plants frequently for aphids, at least once a week.  Examine the undersides of leaves for this insect.  Small numbers can be crushed by hand or knocked off with a strong spray of water.  If the insect is covering 50% or more of the leaf, stronger control measures may need to be taken.  Insecticidal soaps work well against soft bodied insects and can be made by combining a tablespoon of dishwashing liquid to a gallon of water.  This solution can be sprayed using a squirt bottle or pump sprayer on plants.  Aphids must take a direct hit for this to be effective.  Chemicals such as Orthene or malathion can also be effective against aphids.  Regardless of what you are spraying, make sure to get adequate coverage on the plant.  This means the spray should be on the top and bottom of the leaves. 

There are many beneficial insects that will eat aphids, such as lacewings and ladybugs.  One ladybug alone can eat as many as 5,000 aphids in its lifetime!  Because beneficial insects are so important in the ecosystem, be careful that you do not use insecticides when they are not needed.  For instance, the chemical known as Sevin is not effective against aphids, and can be harmful to beneficial insects in the area. 

Farmers' Market Reminder:  If you are interested in setting up at the Richmond Farmers’ Market, the deadline for applying is May 31^st.  Please call the Madison County Extension Office at 623-4072 for more information.

Colorado Potato Beetles are Back
It is time once again to combat the Colorado Potato Beetle.  For those of you who are not familiar with this voracious feeder, the Colorado Potato Beetle is a common insect to the home garden.  This beetle is about ˝ an inch long with black and yellow stripes.  The larvae are dark orange and humpbacked in appearance with a row of black spots along each side.  The adults overwinter and emerge from the soil in spring.  The female will lay her orange-yellow eggs in bunches on the underside of leaves.  There are at least two generations of this insect each year. Both the adult and larva of this insect are considered a serious pest to potatoes, but will also devour tomato, eggplant, and pepper plants. 

  This insect is usually considered a nuisance because it has developed resistance to several types of insecticides.  When an insecticide is used repeatedly, resistance to the chemical can develop in the insect species.  That being considered, the only insecticides that may work on this insect are the chemicals esfenvalerate, permethrin, and cyfluthrin.  Bacillus thuringiensis var tenebrionis (Bt) is effective against small larvae.

  But, just because you see a bug in your garden does not mean that you need to reach for your arsenal of chemicals first thing.  This is true not only with the Colorado Potato Beetle, but with any insect you find in the garden. Insecticides may not only be effective against the pests, but also may kill beneficial insects. Plants can lose up to 30% of their foliage without effecting yields, so do not try to use chemical controls until you see one beetle or larva per plant in your garden.  So, do not use insecticides unless they are truly needed.  Instead, try to use cultural control methods.  One example of a cultural control is going into your garden early in the morning and picking or knocking these beetles off into soapy water.  If you do this in spring before they lay eggs, you can cut down on the number of potato beetles later in the year.  Another option is to use floating row covers.  These covers are light and water permeable.  This type of cover can be made from cheesecloth like materials or sheer drapery fabric.  Row covers should only be used early in the season; once the plants begin to flower it should be removed.

If you have any horticulture questions, please contact me at 859-623-4072 or at amanda.sears@uky.edu.

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