Pest control

Duckweed herbicides safe for frogs

I read on your site about getting rid of duckweed in a lagoon. My concern is for the health of the frogs that eat duckweed. Are the herbicides listed safe for frogs, snakes, deer and other wildlife?

The toxicity to frogs and other wildlife, such as snakes or deer, is slight or less from the herbicides approved for duckweed control in ponds and lagoons. These herbicides undergo extensive testing to determine their risk to wildlife, and the products wouldn't make it to market if they were not safe, when used at labeled rates.

Also, although tadpoles are herbivorous, the natural food for frogs consists of animals that are small enough to be swallowed, such as insects, spiders, crayfish and other frogs. So the likelihood of frogs ingesting enough plant herbicide to be harmful, especially since it's highly diluted in water, is quite remote.

An alternative to using herbicides is to rake or skim the duckweed from the lagoon surface. However, since duckweed is so prolific, you would need to do this repeatedly throughout the growing season.

Bob Schultheis
Natural Resource Engineering Specialist

Structural and termite module training

Do you have a program to make Structural 7A and Termite 7B training available to pest control operators?

Certification and recertification training is available each January at several Missouri locations. At present there is not a training module available for categories 7A and 7B. However, a new manual will be available for wood-boring insects.

Wayne Bailey
IPM/PAT Coordinator

Milk vs. pesticide

My employees claim drinking milk will protect them from any pesticide chemicals they might inhale while doing their work. I am a responsible employer and have provided coveralls, face masks and filters. I'm not willing to perpetuate false notions. Can you inform me about this?

You are correct. The only antidotes for pesticide poisoning are those listed on each specific pesticide label. Few, if any, will list drinking milk as a remedy. MU Extension publication G1915, Pesticide Poisoning Symptoms and First Aid, has more information.

Fred Fishel
Extension Assistant Professor and IPM/PAT Coordinator

Applying pesticides to a golf course

What license do I need in order to apply pesticides to a golf course?

For a license to treat lawns and ornamentals, such as on a golf course, you will need a category 3 license (Ornamental and Turf Pest Control). If you will also be treating bodies of water on the course, you will need an additional license in category 5 (Aquatic Pest Control). All study materials may be obtained by calling MU Publications at 800-292-0969. Ask for the manual MX328, Applying Pesticides Correctly -- this is the study guide that all applicators must be tested on, regardless of category. Also ask for M83, Ornamental and Turf Pest Control manual and M99, the Aquatic Pest Control manual (if necessary). For making reservations to take the state exams, contact the Missouri Deptartment of Agriculture at 573-751-5509. They will set a date for you and mail your necessary paperwork for you to get under way.

Fred Fishel
Extension Assistant Professor and IPM/PAT Coordinator

Pesticide pH

On some material safety data sheets there is a listing "of 1 percent pH" under the pH heading. (Example: pH: 11.0-11.5 1 percent pH: 9.3) It appears that sometimes the pH changes quite a bit and others not very much at all. Could you please explain this?

It's likely that pH for a 1 percent solution is listed on the MSDS because many pesticides are mixed with their diluent(s) and held overnight or longer until they are used. Especially with some insecticides, chemical breakdown occurs in alkaline solutions (pH greater than 7.0). Sometimes this can occur very rapidly. For more information on pesticide stability, refer to PM1017, Effects of Water pH on the Stability of Pesticides.

Fred Fishel
Extension Assistant Professor and IPM/PAT Coordinator