Many gardeners have been battling a variety of pests this season  and even the best gardener can run into tough times once in a while.

So, if you are one of the frustrated gardeners reflecting on the season and trying to figure out how you could have done better, here are some possible reasons why your pest control program was not successful.

 Lack of good penetration of foliage. This often is a problem when spraying for bagworms on junipers. The spray must penetrate the foliage and reach the bagworms toward the inside of the plant. With pump-up sprayers, you may have to push the wand through the outer layer of foliage to reach insects toward the inside of the plant.

 Not spraying where the insects are. Many insects and mites feed on the underside of leaves. If the plants are sprayed over the top, little to no pesticide reaches the pests. This problem is often seen with spider mites on broadleaf plants and cabbage worms on cabbage, broccoli and cauliflower.

 Maturity of pest. Insects become much more difficult to control when they become adults. For example, Sevin does a good job of controlling young, early instar grasshoppers but is much less effective on adults. The earlier you spray the more successful you will be.

 Level of disease pressure. Most of our fungicides are better used as preventatives than as curatives. If a disease gets firmly established, it may be very difficult to bring it back under control. For example, chlorothalonil is effective in controlling early blight and Septoria leaf spot on tomato if used as a preventative. However, chlorothalonil will not control these diseases on badly infested plants.

 Choosing the wrong product. Homeowners often use a product because they have it on hand. However, products differ markedly in how well they control specific pests. Make sure the pest you wish to control is on the label. Unfortunately, even labeled products may vary in effectiveness. Check Extension information for the recommended products.

 High pH spray water. Certain pesticides are not stable in high or low pH water. For example, Captan has a half-life of three hours at a pH of 7.0 but only 10 minutes at a pH of 8.0. Carbaryl (Sevin) has a half-life of 24 days at pH 7.0, but only one day at pH 9. Diazinon is most stable in pH 7 water, with a half life of 10 weeks; at pH 5, it is two weeks. Malathion is stable at pH 5.0-7.0, but rapidly hydrolyzes in more acidic or alkaline conditions.

One of the benefits of gardening is being able to start over. If you are like me and have a lot of replanting and replacing, never fear, fall is just around the corner. Now is the time to regroup and begin making plans to do it better next year.

 Bruce Chladny is horticulture agent at K-State Research and Extension-Douglas County. For more information, call him at 843-7058 from 8 a.m. to 5 p.m. weekdays.