IPM TREATMENT OPTIONS
IPM programs are able to reduce the use of chemicals because they employ a variety of other methods, depending on the crop. Some methods may fit into more than one group, but the categories serve to demonstrate the variety of methods available for pest management.

1. CHEMICAL inputs include, among others, antibiotics, pesticides, pheromones, attractants, repellants, sterilants, and growth inhibitors. Most of us are familiar with this group, especially the pesticides and antibiotics. Chemicals used in the bee industry include Apistan, Coumaphos, PDB, terramycin, grease patties, menthol, and Fumidil-B. Essential oils are a diverse group of natural plant chemicals that hold great promise for pest control.

Some chemicals are less well known. These are the pheromones and the allelochemicals. Insects use pheromones to communicate with other member of the same species. For example, bees use an alarm pheromone to recruit defenders. Pheromones are especially important in the mating process, and researchers have learned to use them in the management of agriculturally important pests. Pheromones may eventually play a role in the management of the small hive beetle and the wax moth. Allelochemicals are involved in communication between members of different species. One group of allelochemicals consists of compounds produced by bee larvae. These chemicals may be used by varroa as cues for host location. Allelochemicals may someday play a role in a varroa trap.

2. CULTURAL methods include the use of crop rotation, pesticide rotation, variation in the timing of planting, fertilization, sanitation, and the planting of trap crops. Several studies have documented that the timing of an application of pesticide can have a major impact on mite populations (Delaplane and Hood 1997). Management techniques that reduce stress make up another large group of cultural methods that can provide a solid foundation for healthy colonies.

3. PHYSICAL methods include the use of heat, cold, humidity, light, and sound. Beekeepers have tried heat for mite control, but without much success. Beekeepers routinely use cold temperatures to kill wax moth eggs in section honey.

4. MECHANICAL methods include hand destruction, barriers, and traps. Beekeepers use many types of barriers for control of skunks, ants, bears and wax moths.

5. BIOLOGICAL methods include beneficial insects and various pathogens. Everybody is familiar with ladybugs, one of ‘the other beneficial insects’ used for control of many pest species. Many farmers also use small wasps called parasitoids for fly control and these creatures might also be developed to control wax moths and the small hive beetle.

6. GENETIC methods include the release of sterile or incompatible individuals and the development of pest resistant stocks. The genetic solution is most desired; yet, it remains the most elusive. Rothenbuhler (1964) demonstrated that AFB resistance was a selectable trait. Recently, Prof. Marla Spivak, at the University of Minnesota, has selected for hygienic bees and improved the technique for identifying hygienic bees (Spivak and Downey 1998). The USDA-ARS lab in Baton Rouge is conducting promising work on mite resistance (Harbo and Hoopingarner 1997). Pest resistant stocks will play a major role in the future of beekeeping. On the horizon are modern molecular techniques that may help to identify desirable genotypes in the laboratory.

7. REGULATORY efforts include import restrictions, quarantines, eradication and suppression. Regulatory efforts have played an important, if often controversial role, in reducing the rate at which pests have spread between countries and throughout countries. Currently, Canada has restricted the import of US bees to prevent varroa mites, Apistan resistant varroa mites and the small hive beetle from entering the country. Some states in the US have restricted the importation of bees to control the small hive beetle.

Historically, beekeepers have not had to deal with many of the realities of modern agricultural life. Before 1984, AFB was the only serious threat to bees, and it was largely controlled by the use of terramycin, rigorous inspection programs, and hygienic management practices. The years 1984 and 1987 were watershed years in beekeeping. They marked a loss of innocence. The arrival of the parasitic mites accompanied by the emergence of a suite of disease causing pathogens propelled beekeeping into the world of modern agriculture. The recent arrival of the small hive beetle, the development of chemically resistant mites and pathogens, and the globalization of the honey market completed this transition. Like it or not, we can not go home again.

A discussion of IPM is important at anytime because it always represents the best long-term approach to the problem of pest management. It is especially important today because of the crisis in mite control, a crisis that was completely predictable from an examination of the history of chemical control of pests in other crop systems. There are five stages common to most crop systems (after Smith 1969):

1. The subsistence phase is characterized by low yields, a poor understanding of the crop system, and limited efforts in pest management. This phase characterizes beekeeping before the discovery of the bee space and the introduction of the Langstroth hive in 1851.
2. The exploitation phase is characterized by an increasing understanding of the crop system, better management, success with chemical controls, increased yields and the development of new markets. This phase corresponds to beekeeping between 1851 and 1997.
3. The crisis phase occurs after many years of chemical dependency. Resistance develops in the pest populations, growers substitute new chemicals for old ones, and the process is repeated. This is where we find ourselves today.
4. The disaster phase is characterized by the need for repeated applications of chemicals for pest control. Two or more chemicals may be required for control. The cost of pesticides increases production costs to a point where the crop can not be profitably grown. Pesticide residues increase to unacceptable levels, and eventually, the pest control program collapses with accompanying bankruptcies and social displacement. This seems to be where we are headed.
5. The integrated pest management phase is characterized by the coordination of multiple tactics that keep the pest population below the economic injury level. The IPM phase can only be achieved after research has first, produced a thorough understanding of the pest’s biology and second, developed multiple techniques for effectively and reliably manipulating the pest population. This is where we need to be.

Sound familiar? Whether we can get to the integrated pest management phase without going through the disaster phase is uncertain. However, beekeepers should not fool themselves into believing that ‘if we just had one more chemical, everything would be alright.’ Pesticides in the absence of a rational pattern of pesticide use cannot and will not provide a sustainable solution to any pest problem.

Nicholas Calderone
April 1999