Summer is upon us once more and so are the summer pests. I've been getting a lot of calls about the latest infestation of cottony maple and cushion scale on a wide variety of plants. Late June and early July are the best times to control these pests since they are at their most vulnerable in the crawler stage. A low rate (1- 1 1/2 %) of horticultural oil or soap will suffocate these pests without doing damage to the plants. For a more natural approach I would recommend releasing Metaphycus helvolus, the soft scale parasitoid or Rhyzobius iophanthae, the singular black lady beetle a.k.a. the scale destroyer.
You should also be on the look out for the Azalea whitefly. Whiteflies will feed on Azaleas, Japanese hollies, Mountain laurels, Rhododendrons and Andromedas. You will know if you have this pest if you shake the plant and very tiny white specks start flying around. Soaps and oils (at the lowest rate) are effective against this pest, but you need to make sure that you are coating the undersides of the leaves completely, since this is where the whiteflies feed. You can also release Delphastus pusillus, the whitefly destroyer to control these pests.
Other destructive pest that you will see starting up at this time of year are Bagworms on Arborvitae and Pine sawflies on Pines. Both of these caterpillars can be devastating to the plants that they infest. I would recommend using a BT (Bacillus thuringiensis) to control these pests. The release of the mini wasp Trichgramma pretiosum, will control these pests very effectively.
Now is the best time to treat for spider mites on Alberta spruces, Hemlocks, Junipers, Spruces and Firs. Use a good quality miticide such as Kelthane or Floramite. Soaps and oils are also effective, but care must be taken when spraying blue spruces or junipers. The soap or oil can remove the blue waxy covering on these plants and turn then green for the rest of the season. The blue coloring will come back with the new growth next year. The natural control for mites is the all purpose predatory mite, Neoseiulus fallacies or the spider mite destroyer, Stethorus punctillum.
One of the biggest problems that our landscapes will be facing will not come from any insect or disease (although this problem will open the door for these pests). This problem is drought stress. The summers on Long Island, as you know, can be dry, humid and hot. This not only affects us but our plants as well. Make sure that that you are giving your landscapes enough water (your plants will need more than your lawn does) when we go into extended periods of no rainfall.
If you are interested in buying the beneficial insects that I have recommended I would recommend that you check out www.shopgreenmethods.com. They have a wide variety of beneficial insects as well as other biological controls.
As always, if you have any questions I would be happy to answer them. You can contact me at 631-691-2381 or 631-466-2930 or by E-mail at aplantdoctor@hotmail.com.
