Pesticides--what are you using these days?

The entire pesticide situation for gardeners is in a state of flux as older products are banned from the marketplace yet few new ones are available. What did you use for carrot rust fly or onion maggots this spring now that Diazinon is gone? My friend Grigg Kellock at Doktor Doom (Ultrasol Industries Ltd. in Edmonton— ) has been working on a solution using their House & Garden Spray, but we’re not sure yet whether it will be workable.

In southern Ontario at least two relatively new pests are now very bad on rose bushes--the Japanese beetle (Popillia japonica) and the rose midge (Dasineura rhodophaga). Japanese bee-tles have been around, especially in the Niagara area, since 1939! Fortunately, they have not yet been found in Alberta or British Columbia, or for that matter, neither have they appeared in Atlantic Canada except for a very limited area in Halifax county. Here in B.C. the Canadian Food Inspection Agency (with the active support of the B.C. government) actively monitors for them with traps.

“They have now more than reached the Toronto area” said a good friend and rosarian. It is a serious pest because not only do the white grubs attack turf and other plant roots, but the adult beetles attack many genera of plants, including roses, devastating both flowers and foliage.

While various insecticides work well, most of those that do are either gone from or about to be gone from the marketplace--malathion, diazinon, chlorpyrifos and dimethoate (Cygon). One that does work, and is still available is Merit, but it is only available to commercial applicators unless you bring some back from the US while they’re visiting!

The old organic insecticides rotenone and pyre-thrum also work, but there is no long-lasting affect. Doktor Doom’s House & Garden Insecticide (25% Permethrin) does have lasting ability and should definitely be tried.

One U.S. garden writer recommends a ‘home remedy’: in a cup of water add 2 ounces of sugar, a mashed banana and a package of yeast. Place in a tub next to your roses and the beetles will want to drink this concoction. They fall in the tub, and you can remove them later. This works for the females but does not attract every male in the neighborhood (the other traps use female pheromones to lure the males), and then you may not have to spray as well.

Though traps are available (Safer’s, for example) the known fact that only about ¾ of the beetles attracted by any trap actually go to it, means that the other ¼ of the beetles are attracted to the plants, so they can be considered a negative. If traps are used, they should be placed at the perimeter of the garden, away from prize plants. Some even recommend giving them to neighbours as gifts so the beetles will be attracted to their gardens!

Now, thinking about the rose midge, let’s look at some recent research conducted for Doktor Doom, specifically their House & Garden Insecticide Spray, regards its effectiveness on rose midge, and other associated insects, and as compared to other generally recommended insecticides. The work was carried out for Ultrasol Industries by Janice F. Elmhirst and Tanya J. Fletcher of Elmhirst Diagnostics and Research in Abbotsford British Columbia.

While the research report is lengthy and includes various scientific explanations, an ‘executive summary’ might well include the following.

“Doktor Doom® House & Garden (0.25% permethrin) applied every two weeks as a light aerosol mist over the plant foliage resulted in a 70% reduction in buds damaged by rose midge compared to the untreated check, with negligible phytotoxicity. The number of dam-aged/infested buds was significantly less than in the untreated check or the Orthene T & O (acephate) standard. Since the plots were not enclosed with screens, some damage could have been due to adult midges migrating into the trial area and between plots within the trial however a similar influx may occur in landscape gardens and nurseries during the growing season. The 14-day aerosol mist treatment with Doktor Doom House & Garden provided excellent control of aphids and thrips also. Monthly mist applications of Doktor Doom H&G were less effective than the 14-day schedule, but still reduced midge damage by approximately 40%. Monthly soil applications of Doktor Doom H&G suppressed midge damage by 50% compared to the check and provided effective control of aphids. Soil applications of Doktor Doom H&G suppressed thrips by about 50% also, but were less effective than foliar mist treatments in controlling thrips, again possibly due to influx of adults from nearby plants.”

While the label of Doktor Doom House & Garden does not presently include mention of its use on rose midge, the Pest Management Regulatory Agency have given Doktor Doom a minor use label amendment to their House & Garden product to include rose midges. Obviously this is a product you can safely use yet this fall on the horrible rose midge.

by Art C. Drysdale