BIOPESTICIDES, BIORATIONAL PESTICIDES AND CONVENTION PESTICIDES— 



Making Sense of It All 



Dr. Stanley R. Swier 



The ornamentals industry is undergoing a re- 

 i^oiution. The tremendous demand for more 

 environmentally friendly pesticides has spurred 

 the development of a large number of new products. In 

 categorizing these products, new terms have been de- 

 veloped. Hopefully, this article will help sort them out. 



BIOLOGICAL CONTROL. 



In classic biological control, an organism is released 

 that parasitizes or eats the pest. In the ornamentals in- 

 dustry, you can buy ladybird beetles, predator mites, 

 lacewings, Encarsia wasps, etc. I won't go through every 

 natural enemy here, but there are several companies 

 that specialize in rearing predators and parasites. The 

 use of natural enemies has not been widely accepted 

 in the industry for several reasons: 



(1) the difficulty in understanding the complex rela- 

 tionship between the predator and prey, 



(2) the need for extensive monitoring, 



(3) the problem that the use of conventional pesti- 

 cides to control other diseases and pests will 

 often harm the natural enemy you're trying to 

 promote, and 



(4) inconvenience. 



We don't yet have cookbook methodology on how to 

 use natural enemies for every pest and crop combina- 

 tion. Yet this is what most growers will need. 



also many small distributors of nematodes that don't 

 use trade names, but use the name of the nematode 

 (i.e., Steinernema carpocapsae) . Nematodes that are distrib- 

 uted on a national basis are usually in some sort of 

 dormant state and are mass-reared. In mass rearing, the 

 quality of the nematode can suffer. 1 have been sent 

 dead nematodes for my research. The reason 1 know is 

 that check every batch. Another problem with nema- 

 todes is that storage life is short (three to six months). 

 Nematodes also require a high volume of water in ap- 

 plication, moist soil, and repeated applications How- 

 ever, when properly used, nematodes can be an effec- 

 tive insect control agent. Be sure you are buying health 

 nematodes. Check yourself to be sure they're alive! 

 Also, some species are better soil nematodes, while 

 others tend to be surface ambushers. Talk to your sup- 

 plier or give me a call to determine which species to 

 buy. A local supplier may provide more information and 

 better quality control. Overall, nematodes have not 

 been able to develop a large market and a major sup- 

 plier (Biosis) has filed for bankruptcy. 



Why would a greenhouse grower 

 bother to learn how to use 

 Encarsia wasps for the control 

 of whiteflies when Marathon will 

 do it very effectively 

 and much more conveniently? 



BIOPESTICIDES. 



These products are either living organisms or toxins de- 

 rived from living organisms. However, they use conven- 

 tional spray methodology to be delivered to the target 

 pest. Some are exempt from EPA and state registration 

 because they are not considered pesticides, but multi- 

 cellular biological control agents. Here are some ex- 

 amples. 



Nematodes. Nematodes are small roundworms that are 

 parasitic on many forms of soft-bodied insects. They are 

 EPA-exempt from registration. The nematode doesn't 

 actually kill the insect, but it carries a bacteria that 

 does. Once the insect dies from the bacterial infection, 

 the nematode feeds on the body. Two trade names that 

 are familiar to you are XGnat and Scanmask. There are 



Bacteria. There are species of bacteria that are most 

 commonly used. Bacillus tkuhngiensis subspecies kurstaki 

 (Dipel, MVP) is primarily effective on small caterpillars. 

 Bacillus thuringiensis subspecies israeliensis (Gnatrol) is pri- 

 marily used against fungus gnat larvae. B.t.i. is also 

 used against mosquitoes and blackflies in large-scale 

 control programs on the New Hampshire seacoast. For- 

 mulations of these bacteria contain their endotoxins, 

 not the actual bacteria. EPA considers them more like 

 chemicals and they are not EPA-exempt. Unprotected 

 workers must still obey a four-hour re-entry interval 

 when using B.t. A new strain of B.t. (B.t. japonica bui bui) 

 was being developed for Japanese Beetle larval control. 

 Our results looked very promising. Unfortunately, 

 Mycogen ran into some costly production and formula- 

 tion problems and dropped development. 



AUGUST & SEPTEMBER 



997 



13 



