Merit 75 WP - Questions & Answers

One 2oz jar of Merit WP contains enough product for about 30 cumulative inches of tree trunk diameter (at the highest concentration for systemic control). These small 2oz jars are usually purchased by people who only have to treat one or two trees or shrubs. When you need to treat several trees the Merit 75WSP envelope is usually the way to go. One envelope of the Merit 75WSP contains enough product for about 96 cumulative inches of tree trunk diameter at the highest concentration. As a low cost alternative we recommend Dominion 2L which has the same active ingredient as Merit and treats the same insects.  One bottle of Dominion 2L contains enough product for about 137 inches of tree trunk diameter at the highest concentration.

We agree, the directions can be very confusing. You will dilute the 1.6 oz pack in at least 10 gallons of water and pour the dilution around the base of the tree. You will need to use 1.6 oz (1 packet) MERIT 75 WSP per 24 to 48 inches of trunk diameter.

The Merit 75 WP product label is one of the most confusing of all the products that we sell.  You need 1.4 level teaspoons of Merit per inch of diameter. This is the highest rate and should be used for all boring insects. The amount of water that is used will vary depending on soil conditions and volumes that are easy for applicators to use. The minimum amount of water that should be used is 1 pint per inch of tree diameter but you may use 1 quart -1 gallon of water per inch as well. Denser soils such as clay do not accept water as readily, so the lower volume of water is suggested.  Since sandy soils can accept more water, using the higher volume of water is preferred.

Merit 75 WP is labeled for adelgids and will be able to help with hemlock wooly adelgid infestations. Because hemlocks are shallow rooted, a soil drench with Merit 75 WP can be effective. Whatever method is being used to make a soil drench, whether using power equipment, a bucket or watering can, it is important to make sure the application is evenly distributed and does not run off. Soil treatments should be made when the soil is moist. Fall to early winter and spring to early summer are recommended periods for making soil applications for the HWA. It can take 2-3 months for imidacloprid products to be translocated through trees that are about 15 inches in diameter. This process may be faster or slower, depending upon the size and health of the hemlock and other environmental conditions during and after the application.  It is advisable to make soil applications of imidacloprid products to hemlocks before they become heavily infested and stressed by the HWA— to ensure good translocation through the tree.

Merit, or the active ingredient in Merit, Imidacloprid, is the best product for grub control. It is important to start treatment prior to egg hatch. For optimum control irrigation or rainfall needs to occur within 24 hours of the application to move the product through the thatch layer and into the soil. You can contact your local cooperative extension office to see when egg hatch normally occurs in you region. Dominion 2L contains the same active ingredient as Merit and can be used as a money saving alternative.

Unfortunately, we do not sell any injection rods or kits due to their cost and that they typically are used with expensive large tanks and gas powered systems that are not really economical for a homeowner to purchase.  However, you can apply the Merit as a soil drench which prevents you from having to inject it, or many of our homeowners just use a long piece of rebar or thin steel and use a hammer to make injection holes around a root system and then fill the holes with the merit.

Merit 75 WP can harm beneficials such as earthworms.

The trees should be treated as separate trees. When applying merit your aim is to treat the roots that are close to each tree, not at the outer limits of the dripline. Instead go out about a foot from the base of the tree and do the application there in a bout a two foot band.

We recommend Merit for cottony maple scale. When dealing with soft scale insects, Merit can be applied as a root/soil drench. Insecticides applied to the soil are taken up by the roots and translocated throughout the tree or shrub. Root/soil drenches offer the advantage of requiring no special equipment to apply (other than a bucket or watering can). However, surface layers of organic matter, such as mulch or leaf litter, can bind the insecticide and reduce uptake. Before applying drenches, it is important to remove or pull back any mulch or dead leaves so the insecticide solution is poured directly on the mineral soil. It is also important to keep the soil around the tree or shrub moist for the next 7-10 days after applications to encourage uptake. Low cost alternatives to the Merit would be Dominion 2L or Mallet.

You want to use 4 teaspoons Merit 75 per 1,000 square feet to treat for Chinch bugs.

There are aproximately 40 teaspoons in a 2 oz jar of Merit 75WP.

Merit 75 WP is not labeled for bagworm control. We recommend using Talstar P for bagworm control. Timing is key when spraying for bagworms. Apply when larvae begin to hatch and spray larvae directly. Applications when larvae are young will be most effective. You can check with your local Cooperative Extension Office to see when bagworms become active in your region.

Bayer Advanced Natria Multi insecticide is labeled to treat whiteflies and mealy bugs among many other pest. It is ready to use and can be applied to ornamentals.

Merit 75 WP is labeled for Mealybugs, Chafers, Chinch Bugs, Garden Beetles, Japanese Beetles, Billbugs, Mole Crikets, grubs and others. Please see the product label for a complete list.

Merit 75 is not actually labeled for squash bugs but squash bugs that try to feed off of treated plants would surely be effected. Merit 75 is most likely not labeled for squash bugs because it cannot be used on most edible plants which are the ones that will most likely be infested by this pest. We do carry Bayer Advanced Fruit, Citrus and Vegetable Insect Control and while it does share the same active ingredient as Merit 75 the formulation is a bit different which is what allows you to use it on edible plants.

You should do a foliage spray with the Merit WP as waiting for the product to be taken up by the roots from soil drench and trans-located through the plant can take too much time when you already have a damaging pest population. You will need to use 0.25 tsp of Merit per 2.5 gallons of water and thoroughly spray the foliage (don't forget to spray the underside of leaves). Foliage sprays will also work systemically. In the future you can choose to do soil drenches before the pest population has a chance to build. You will need to use 0.7- 1.4 level teaspoons of MERIT 75 WP Insecticide per foot of shrub height or 1 to 2 ounces per 30 cumulative feet of shrub height mixed in at least one pint of water per foot of shrub height. You will be required to pull back mulch or leaf debris near the root base prior to the application and you will be required to water in the application with about 1/2 inch of water. It is important to keep the soil moist for at least two weeks following the application to help with root uptake.

Per the Merit 75 WP label: The addition of a nitrogen containing fertilizer, where applicable, into the solution may enhance the uptake of the active ingredient.

Merit 75 WP is not labeled to treat Gypsy Moths. Using an insect spray such as Monterey Insect Spray containing Spinosad is the most effective way to treat for these types of caterpillars. When sprayed on the foliage, this products works by poisoning the caterpillars feeding on the leaves. It is more effective and generally lasts 3-4 weeks.

Garden Insect Spray with Spinosad is a concentrate that can be applied with trigger, hand-held, or hose-end sprayers. This product is not a synthetic chemical, but a bacterial product produced by fermentation. It is fast acting and odorless.

With a systemic application of a product like Merit to the root zone, it can take a couple of weeks for a large to tree to complete aborb and have the ingredients translocate all the way through the plant. Some borers once they have started damage to a tree do such quick harm to it that the tree cannot be salvaged or saved even with the strongest insecticides. Below is a link to information on the bronze birch borer and the average timing, life cycle and treatments that can be used. 

 

http://www.extension.umn.edu/garden/insects/find/bronze-birch-borer/