The heat of summer is starting to take its toll on landscapes. Flowers are fading, weeds are thriving, and bugs and disease are becoming more of an issue. With so many pests and so many chemicals to choose from, gardeners will ask: “Why did the spray that I bought not work?” Here are the top 10 reasons why homeowner lawn and garden chemicals fail to do their job.

¢ Pest resistance: Because chemicals have been around so long, several insects and diseases have become immune to their deadly effects. To help prevent this, alternate chemicals each time you spray. Likewise, consider using soaps and oils for insect control.

¢ The product is not designed for the intended use: The best example of this is treating for grubs to control moles. There is more to mole control than killing grubs. When treating general pest problems, do a little research and use only those methods that have been proven effective.

¢ Product degradation: Chemicals do not last forever. As a general rule, do not try to store chemicals for more than a season or two. Buy only what you can use in one gardening season. If you have old chemicals, dispose of them properly. Lawrence has a Household Hazardous Waste Facility, and you can call 832-3030 to schedule a drop-off appointment.

¢ Premature evaluation: Most chemicals do not work overnight. Be patient and re-evaluate the success of your sprays over a longer period of time.

¢ Improper application rate: Do not garden by the old adage: “If a little is good, a lot must be better.” More is not always better, and a little may not suffice. When mixing and applying lawn and garden chemicals, always read and follow all label directions, including mixing rates. Applying too much can kill the plant you are trying to protect.

¢ Misdiagnosis: Many garden pests look and act alike but require different treatments. Make sure you have completely and accurately identified all the pest problems before spraying. Then choose the best control option. Spraying the wrong product on the wrong pest may cause more damage than the original pest inflicted.

¢ Wrong timing: Many pests are easy to control when young but become impossible to control when they are adults. Similarly, many diseases need to be prevented and not sprayed when they are spotted. Learn the optimal time to try to control your pests. Timing may be the difference between success and failure.

¢ Failure to follow up properly: Some chemicals need to be watered in to be activated, while others can be washed off by rain. Find out how the chemical you applied should be treated after application. Likewise, a follow-up treatment may be recommended for best results. Other factors such as mowing weeds before applying weed killers, drought conditions that hinder plant growth, temperature extremes and dirt or dust on the leaves that prevents spray contact may prevent success.

¢ Poor application technique: When spraying chemicals, take your time and do a good job. A hurried application over the top of leaves to try to kill insects hiding under the leaves will result in failure. Using a spreader-sticker such as soap can help chemicals stick to slippery, glossy leaf surfaces. In all cases, good, complete coverage of both upper and lower leaf surfaces is essential.

¢ You took the product home but never applied it. A chemical has to be used before it can be effective.