With increased Federal regulation of pesticides, the range of pesticide products available to homeowners at retail outlets such as garden centers and nurseries is narrower than a few years ago. With fewer choices, it's especially critical that homeowners read the labels on these products with great care in order to avoid misuse.
It's all too easy to misunderstand a pesticide label. A good example is "Ortho Home Orchard Spray," a very widely sold product that is a mixture of a fungicide (captan) and two insecticides (malathion and methoxychlor). The label recommends applying the product during the bloom period on peaches, cherries, and apricots. The major pest targeted during the bloom period is brown rot, a fungal disease. However, the insecticide components of "Home Orchard Spray" are highly toxic to the bees that pollinate the blossoms, so a spray when bees are active can devastate their populations and result in poor fruit set. Another part of the "Home Orchard Spray" label includes a caution against using the product when bees are active, but this is easily overlooked unless the label is read carefully and thoroughly. Another problem is that many people are unaware of the usual timing of bee activity (active during midday, less active at dawn and dusk).
This example brings up a fundamental drawback of "combination" products such as "Home Orchard Spray": often, a spray is applied when one of the pesticides (the fungicide or the insecticide) has no benefit to the crop. The result is that these pesticides are wasted.
At times when only a fungal pathogen or an insect pest, but not both, are being targeted, a fungicide or insecticide used alone makes better environmental sense. Unfortunately, many retail outlets in Iowa offer few choices in fruit pesticides. For the above example (brown rot control during bloom), however, there is a more specific option, Daconil 2787. This fungicide, sold widely under the Ortho label ("Ortho Multi-Purpose Fungicide") and others, controls brown rot effectively without endangering pollinators.
Buying and using several specific pesticides may be less convenient that the "one size fits all" approach of combination products, but it's a positive step toward environmentally responsible pesticide use.
This article originally appeared in the May 6, 1992 issue, p. 75.