Pesticides and Turf: Expert Q&A with William Harrison of Target Specialty Products

Staff Report

''There are a lot of people that do a foliar treatment with a Pyrethroid to control aphids. Although this will help control the aphids, it has a down side, as an application of a non-selective foliar insecticide will also kill any beneficial insects that are present.''

William Harrison currently holds the reigns as Target Specialty Products Business Manager for the professional vegetation management market. Harrison is responsible for coordinating and managing all of Target's activities within this market.

Prior to becoming a business manager, he was a field representative in the Southern California area. Before joining Target five years ago, he was an in-house consultant for a corporate farming operation, and managed an agricultural pest control business. He is an adjunct professor for California State Polytechnic University, Pomona, teaching industry-related courses. Harrison has been a licensed pest control advisor for more than 20 years. He also holds a certified arborist and crop advisor license.

The editors at Landscape Contractor/DBM sat down with Harrision recently to get his views on turfgrass pesticide use, and the state of the industry.

Q: How long have you been in the pesticide industry?

A: I have been doing weed control on one level or another for more than 30 years - from spraying to consulting.

Q: What is the strangest thing you have seen in your career concerning weeds or pests?

A: I have witnessed more than one person spraying various landscape shrubs and hedges with Roundup to kill the weeds growing among them.
They thought they could kill the weeds and not hurt the landscape plants.

Q: What is the best treatment for crabgrass and goose grass?

A: With the loss of MSMA (see sidebar), crabgrass and goose grass are going to be major challenges for turf managers. The only way to be truly effective in keeping these weeds at bay is to use an effective pre-emergent herbicide. With limited post emergent materials the logical choice is take care of the problem before it gets started. The problem with goose grass is that it has an extended germination period and people may hesitate to make a second pre-emergent application in late spring. Unfortunately, after emergence there are not any good materials to control goose grass.

Goose grass

With crabgrass you have two post-emergent options; the first is the use of Dimension at the pre-tiller stage of the crabgrass. Although Dimension is considered a pre-emergent herbicide it does have post-emergent control on young crabgrass. The other option is Drive. Most of the time Drive will do a good job, however there are now cases of resistant smooth crabgrass, so care should be taken to use Drive at correct rates and as early in the development of the crabgrass as possible.

Q: Are there integrated pest management practices you advise for top weed problems?

A: Pesticides alone cannot control weeds; therefore it is important to employ good horticultural practices. Water management is critical, too much can shift the advantage to the weeds. On the other hand, too little water can stress the turf, which leaves it susceptible for more competitive weeds. Good balanced nutrient management will maximize the growth and vigor of the turf. The more vigorous the turf, the better it is capable of competing with the weeds. Soil management is also very important. If the soil is compacted to the point that the turf struggles to grow, there are several weed species that will thrive in this situation and can even take over the area. When you talk about integrated pest management in turf, you must take into consideration all aspects of managing the turf to have the best program possible.

Target Specialty Products' top selling insecticide is Merit; it has the versatility to control aphids in plantings, but also grubs in turf, and it does not compromise the beneficial insects.

Q: What is the biggest bug problem you see out there?

A: Year after year contractors tend to spend quite a bit of money on aphid control. Tree borers and mites can be a problem at times, but consistently aphids are a problem.

Q: What pesticides are most effective to get rid of aphids?

A: There are a lot of people that do a foliar treatment with a Pyrethroid to control aphids. Although this will help control the aphids it has a down side, as an application of a non-selective foliar insecticide will also kill any beneficial insects that are present. Any time you have an insect problem you should always take into consideration what beneficial insects are present and how they can help you. To this end, the Neonicotinoids, such as Merit and Safari, effectively control the aphids while having a minimum impact on the beneficial insect population. Although foliar applications of these materials can be made, I encourage applications such as soil drenches, basal bark treatments or tree injections. These methods of application minimize the amount of material that is required while still controlling the aphids. Additionally these application techniques can be employed in areas where it would be a challenge to do a foliar spray.

''... the Neonicotinoids, such as Merit and Safari, effectively control the aphids while having a minimum impact on the beneficial insect population.''

White Grubs

Q: How does one deal with white grubs? Are there integrated pest management practices you advise for grubs?

A: There are no good integrated pest management practices for control of white grub. With the loss of Dursban, white grub control has become more challenging. Although there are still good materials to control the grub, the timing is much more critical in order to be successful. I believe the best choices for grub control are Merit, Acelepryn or Arena. There are also parasitic nematodes that can be used to control the grubs if the use of a conventional chemical is not desired.

Q: What are the top insecticides and herbicides that a lawn care professional should have in their arsenal?

A: Specifically with insecticides I hesitate to mention any one material, the reason for this is every situation is unique unto itself. From this standpoint I encourage everyone to take advantage of a licensed advisor to make the best choice for insect control.

For weed control I believe you need a good pre-emergent and a good selective post-emergent herbicide. As I previously mentioned I am a fan of Dimension only because it can pick up young germinated crabgrass. For post-emergent control I lean heavily on 2,4-D, only I would recommend it used in a mixture to enhance performance.

What is MSMA?

Since the 1960s, Monosodium methanearsonate (MSMA) was a herbicide used to manage infestations of various crabgrass species (Digitaria spp.), as well as goosegrass (Eleusine indica) and dallisgrass (Paspalum dilatatum) in warm-season turf. Water samples from two golf courses in Florida tested high in arsenic, spurring a ruling by the United States Environmental Protection Agency (EPA) to cancel the registration of MSMA in all aspects of agriculture, including turfgrass management.

In September, 2009, the EPA announced the final decision regarding the use of MSMA for agricultural weed management. Impacts on the turfgrass industry were significant, with repercussions that changed the weed-control strategies of turfgrass maintenance professionals nationwide.