A Review of IPM Tactics 



by Dr. Stanley R. Swier 



IPM is a new buzzword heard 

 more and more throughout 

 the hortic ultural industry . In- 

 tegrated Pest Management 

 is simply the use of a variety 

 of techniques to reduce pests 

 without the sole reliance on any one (i.e. 

 pesticides). The exclusive use of pesti- 

 cides to control pests is no longer an ac- 

 ceptable option for political, sociologi- 

 cal, and biological reasons. There is a 

 tremendous fear of pesticides by the 

 public. Although this fear is exagger- 

 ated, the perception is that all pesticides 

 are extremely dangerous. In this case, 

 perception becomes reality and it is dif- 

 ficult for the industry to fight it. In addi- 

 tion, the concern for protecting ground- 

 water, endangered species, the environ- 

 ment, and human health all translates 

 into tougher state and federal regula- 

 tions of pesticides. The cost of develop- 

 ing and registering a new pesticide is 

 now around 40 million dollars. Due to 

 the small market of the nursery and 

 greenhouse industry, few new pesti- 

 cides will be available to replace those 

 we are losing. Those pesticides which 

 remain in our inventory, are becoming 

 useless due to insect resistance. There- 

 fore the wise manager will not rely 

 solely on hard pesticides and will look 

 to other methods to pre vent pest buildup. 

 Admittedly, IPM in New England orna- 

 mentals may be more difficult because 

 our industry is composed of many small 

 family operations. For economical rea- 

 sons, these operations are overcrowded, 

 contasin a wide variety of plant mate- 

 rial, and have an uneven turnover of 

 plants. However, we must try to do bet- 

 ter to implement IPM. Many of the 

 following suggestions are nothing new, 

 but too many growers are forgetting the 

 basics. I will also point out the problems 

 you will face in trying some new IPM 

 tactics. 



Exclusion and Sanitation: 

 It is easier to prevent pest problems 

 by not allowing them into your green- 

 house or nursery than to try to control 

 them after the population explodes. Not 

 enough time is spent on inspecting plants 

 before you accept shipment. After the 

 plants have been in your possession for 



awhile it is difficult to prove they came 

 infested with pests. Greenhouse vents 

 should be screened. The new spun 

 bonded materials will keepout the small- 

 est insects but they do reduce air circu- 

 lation. Weeds in and out of the green- 

 house becomean excellent reservoir for 

 reinfestation of insects and mites. Elimi- 

 nate weeds immediately outside of 

 greenhouse walls, doorways, or side 

 vents. Don't forget to destroy old plant 

 material and fumigate between crops to 

 destroy any leftover insects. 

 Biological Control: 



Biological controls vary from those 

 that are simple to use to the very com- 

 plex. The simplest are those that are 

 used like pesticides. They are stored 

 until needed, mixed up, and then ap- 

 plied. Bacillus thuringiensis (Dipel, 

 Thuricide) is very effective against many 

 caterpillars but is very short-lived and 

 frequent applications are necessary dur- 

 ing a prolonged outbreak. For some 

 species, only the young caterpillars are 

 conu-olled by Bt, so proper timing is 

 very critical. Bacillus thuringiensis is- 

 raeliensis (Vectobac) has been shown 

 to be effective against fly larvae such as 

 fungus gnats and shore flies. BTi can be 

 easily applied through the irrigation 

 system. 



There are several species of nema- 

 todes which are available commercially 

 that can be used against soft-bodied 

 insects such as grubs and caterpillars. 

 These species of nematodes only feed 

 on insects and do not harm the plant. 

 Presently, nematodes work best in con- 

 tainerized plants against soil pests such 

 as the black vine weevil. The routine 

 use of nematodes has been hindered by 

 high cost, poor storage ability of the 

 formulations, high soil moisture require- 

 ment, U-V light sensitivity of the nema- 

 todes, and erratic performance. Further 

 research will solve many of these prob- 

 lems and nematodes will gain wider ac- 

 ceptance. The use of nematodes will re- 

 quire that the grower refrain from using 

 other pesticides which may be harmful 

 to them. 



Some species of fungi are specific to 

 insects and are already commerically 

 available ( Vertalec , Mycotel.) Fungi can 



be very effective against aphids and 

 whiteflies but have two disadvantages. 

 They require high humidity which en- 

 courages plant pathogenic fungi and 

 fungicides used to control plant dis- 

 eases will adversely effect the insect 

 pathogenic fungi. In order to use these 

 fungi properly, high humidity and al- 

 tered fungicide schedules are neces- 

 sary. 



Interest in predators and parasites is 

 increasing. The use of these organisms 

 is very complex because they have spe- 

 cific environmental and host require- 

 ments. Predators and parasites tend to 

 work best under the following condi- 

 tions; 1 ) only one or two crops are being 

 grown to simplify logistics; 2) crops are 

 longer term in order to give the biologi- 

 cal control agents time to work, 3) there 

 are few other insects on the crop be- 

 cause spraying for other insects kills 

 the biological control agent; 4) to ap- 

 pease consumers, the biological control 

 agent is not present (its purposely killed 

 with insecticides before the plant is sold, 

 or does not usually appear on the plant 

 product sold (i.e. greenhouse tomatoes); 

 5) the grower is willing to thoroughly 

 understand the complex relationship 

 between the plan t pest and control agent 

 and 6) willing to devot e the time to alter 

 the environmental conditions, chemical 

 control program, and crop production 

 practices to make biological control 

 work. Not all pests can be controlled by 

 biological agents. Some, like cyclamen 

 mite, require preventative chemical 

 control. 



Soft Pesticides: 



As traditional insecticides become 

 less effective and more expensive, there 

 is more commercial interest in develop- 

 ing alternatives. Safer's soap can be 

 used against a wide variety of insects. 

 However, to be effective, thorough 

 coverage and frequent application is 

 necessary. A horticultural oil is now 

 available for greenhouse use. Sunspray 

 Ultra Fine Spray Oil was recently regis- 

 tered in New Hampshire. We need to 

 increase our use of horticultural oils in 

 both the dormant and growing season. 

 Unfortunately, much prejudice exists 

 against oils because the old style oils 



