SEPTEMBER
2006

 

 

 

By
B. Rosie Lerner
 
Purdue
Extension
Consumer Horticulturist

 

 

 

 

 

09-07-06

Question and Answer

Q. I have had Japanese beetles in my yard for the past several years -- and each year the infestation increases. This year, they are really profuse -- everything in the garden is under attack! If I bump a branch when mowing, I am showered by them. I have about one acre surrounded by farmland. This year it is corn; but I see no sign of infestation on the corn stalks. I have been shaking them (the beetles) off the shrubs, etc., and catching them in pails of soapy water. This is tiring and then poses a problem of disposal, as they smell awful. So I have to bury them, which is also tiring.

A. It does seem that many gardeners have observed large numbers of Japanese beetles in their yard and garden this year. The adult beetles are usually active from mid-July through August. So, by now, they should be on the decline.

Favorites for Japanese beetles include linden, crab apple, rose bushes, grapes, plum and other fruit trees, and several garden-variety vegetables. (I've also personally observed that wisteria is among their favorites in my garden!) Many plants can tolerate an amazing amount of feeding, but others may not fare so well. Plants that are particularly at risk include young, recent transplants or those that are stressed from other factors, such as drought, heat and disease.

Hand picking as you've been doing can be effective for smaller populations and/or to protect a few particularly prized plants and must be done at daily to be effective. For vegetables and fruits, applying a fine mesh netting over the plants can help exclude the pests. Several insecticides are labeled for protecting plants from Japanese beetle defoliation. Purdue Extension has an excellent bulletin on managing Japanese beetles in the home landscape, available online at http://www.entm.purdue.edu/Entomology/ext/targets/e-series/EseriesPDF/E-75.pdf.

Q. I'd like to know what can be used for weed and thistle control and what time of the year it can be used with strawberry plants. I've tried Preen and it hasn't helped.

A. There is no easy solution for the small backyard grower because most herbicides that will control thistles and other persistent weeds will also harm the strawberry plants. Home gardeners with small strawberry patches can get pretty good weed control by using clean, weed-free mulch, renovating the patch after harvest, and hand pulling or hoeing as needed. For particularly weedy patches or larger patches that are more difficult to keep up with, a herbicide may be helpful, but needs to be labeled for the type of weeds you're trying to control, as well as for use in strawberries. Some products are effective against only grassy weeds, while others only broadleaved weeds, which of course then would be potentially harmful to the strawberries. Timing of the application will depend on what you're trying to control as well. Some products must be applied before the weed seeds germinate, and others are applied to the actively growing weeds. Annual grasses and some broadleaved weeds can be prevented by applying a pre-emergence control such as Preen (active ingredient is trifluralin) or dacthal. An organic alternative is corn gluten meal, available from many garden centers and mail-order/Web stores.

Perennial weeds are best controlled in June-bearing strawberries when renovating the bed immediately following your last harvest. Shallow cultivation can help, and there are a few herbicides that are labeled for use in the strawberry bed after the strawberry plants have been mowed off. For more information on management of strawberry beds, see Purdue Extension publication http://www.hort.purdue.edu/ext/HO-46.pdf. Commercial growers and large-scale home growers will find additional information on weed and pest control in the Midwest Small Fruit Pest Management Handbook http://ohioline.osu.edu/b861/.

Q. I have a question about our tomatoes. We have a problem keeping the blooms from falling off. They just dry up and fall off. Someone told us we were using the wrong fertilizer. I think it's triple 12, and then my husband side dresses them with nitrogen. Are we using the wrong fertilizer? We get a few late tomatoes.

A. Blossom drop on tomatoes and many other vegetables was a common problem this year due to first the cool temperatures in June, followed by extreme high temperatures later in the summer. The optimum temperature range for pollination of tomatoes is 70-82 F. Temperatures below 55 F or above 90 F will cause blossoms to fall without setting fruit. A 12-12-12 fertilizer, with additional side dressing of nitrogen, should be just fine for raising tomatoes.

For more information on blossom drop of tomatoes and other vegetables, see my articles at http://www.hort.purdue.edu/ext/springunkind.html and http://www.hort.purdue.edu/ext/hotweather.html.

 

Writer: B. Rosie Lerner
Editor: Olivia Maddox,