Pest Alert

  • Aphids still active – Keep your eye out for aphids on your veggies, flowers fruit trees and other woody plants. Even if you think you have gotten them under control keep in mind that a single female can lay hundreds of eggs that can hatch into more female aphids without being fertilized. The warmer weather shortens the time needed for the egg to hatch and the nymph to become a reproductive adult Use a strong stream of water to knock them off plants or use an insecticidal soap spray (neem based insecticidal soap offers additional protection.
  • Leaf miners – These tiny larvae burrow inside the leaf leaving irregular tunnel tracks on the leaves of its host. The larvae can be from tiny black flies (most usual on vegetables) or from various moths and beetles. Unfortunately external sprays won’t reach these pests. Catch them early and remove infected leaves when possible. There are native wasps that will parasitize them. On smaller plants live beets and chard use a floating row cover (light floating fabric of spun polyester called Remay) before damage is apparent. Also Keep an eye out on columbines, Camperdown elms, evergreen hollies, poplars, oaks, rhododendrons,and locust trees.
  • Spider mites – The adults of these can be seen with the eye but may go unnoticed when the populations are small as the insects can be from 1/75-1/150 of an inch. Larger populations become more evident when the leaves become discolored yellow white or bronze or the insects fine webbing becomes apparent (in some species) can be found on vegetables like beans, cucumbers, eggplants, melons peppers, pumpkins, squash, tomatoes and zucchini. Many house plants and annuals like impatiens, geraniums, zinnias, perennials like iris, lilies, hollyhocks, delphiniums, dianthus (carnations pinks, sweet William), gladiolus, phlox, violas. As well as shrubs and trees like roses, cherries, plums, apricots, lilacs, willows, western red cedars, jasmines, and hemlocks. Spider mites prefer warm dry conditions so the first line of defense is spraying the undersides of the leaves (where they congregate) with cold water. The next line is insecticidal soap, horticultural oil (summer oil) and neem oil.
  • Whiteflies – Although they usually won’t overwinter outdoors here (occasionally they can) the usual source of these insects is infected plants grown in greenhouses. They may appear clean but there may be eggs present which are not susceptible to most spray controls. My favorite method of control is a shop vac and a long extension cord. I shake the leaves and suck up those fast moving sap suckers. They can attack many plants but seem to favor strawberries, many annuals rhododendrons (and azaleas) grapes, squash, tomatoes, peppers and eggplants. There are many natural controls already in your garden like ladybugs and parasitic wasps. You can also control the wingless nymphs with insecticidal soap, horticultural oil (summer oil) or neem oil.
  • There is a second generation of codling moths emerging in mid-July. Trap adults with Codling Moth Traps and control feeding larvae with neem oil.
  • Black Spot – Roses and some relatives like photinia will be showing sings of this fungal disease. First line of defense is keeping water off the leaves and grow plants in areas with good air circulation. Avoid overhead spraying of susceptible plants. Another first line is removing all infected leaves that appear. You can also spray with an appropriate fungicide like Rose 3-in-1 (neem oil) weekly into the fall.
  • Botrytis Blight – Another fungal disease that is promoted by high humidity conditions so similar to black spot avoid overhead watering and areas with poor air circulation. It can attack just about any plant especially those that have been injured or wounded. Remove all infected plant parts and keep flowering plants deadheaded as the fading flowers can be attacked.
  • Verticillium wilt – a soil borne fungal disease that overwinters in the soil and in plant debris. It will attack many cultivaated plants like tomatoes, peppers and eggplants, chrysanthmums, strawberries, roses, ornamental fruits maples, cherries, and peaches as well as other ornamentals. The virus usually enters through the roots and infects the vascular tissue. The result is water and nutrients cannot move freely in the plant and it slowly yellows, withers and dies. The fungus can remain in the soil for over 10 years so control includes rotating susceptible vegetables and planting resistant species of plants in infected soil.