What is IPM? IPM combines several pest control strategies that are complementary to reduce a pest population to an acceptable level (i.e. below its economic injury level) whilst minimising the negative impacts on the environment and human health (Harper, 2006). Crop quality is not compromised and yield is often enhanced. The European Union has announced that by 2014 all farmers must use IPM in order to make agriculture more sustainable. Example Illustrating the Importance of IPM Farmers in China growing genetically modified Bacillus thuringiensis (Bt) cotton have had problems with secondary pest outbreaks of mired bugs. Mired bugs were never a problem under conventional pest management of cotton because they were killed by the broad spectrum pesticides. As a consequence of not using IPM, net profit has reduced as farmers must now spray more pesticides on Bt cotton than before (University of Warwick, accessed online 2011). Use of IPM is therefore extremely important. Possible Components of IPM - Chemical pesticides can form a valuable part of IPM but they must be used sparingly (i.e. not as a blanket solution) to reduce the risk of resistance evolving as they are a precious resource. A new generation of chemical pesticides have and are being developed. These have fewer negative impacts and so they will become increasingly important and perhaps change public perception on chemical pesticides. Combining their use with biological control agents however will need careful consideration so that the biological agent is not targeted. - Cultural farming practices such as intercropping, undersowing, planting or maintaining hedgerows to encourage conservation control. - Decision support tools for example forecasting (i.e. predict time of migration onto crop to access the level of risk- Myzus persicae provides a good example) and work out crop thresholds (i.e. economic threshold, economic injury level, etc). - Biological control agents including predators, parasitoids, pathogens and competing species. Microbial biopesticides are ideal components of IPM as they do not target beneficial insects or natural enemies and can be used with other biological control organisms. - Breeding of resistant cultivars Examples of IPM in use 1. To control third instar scarabs, pests of turf, the insecticide imidacloprid can be used with entomopathogenic nematodes (Lacey et al, 2001). 2. Bacterial and fungal entomopathogens can be used in combination to control mosquitoes (Harper, 2006). 3. To avoid target populations evolving resistance to Bt IMP is vital. Strategies adopted include high concentration/ volume of inoculation, use of different Bt toxins at different times and use of several different toxins at the same time (Lacey et al, 2001). Another technique used to avoid pest resistance against genetically modified Bt-crops is to plant non-Bt crops next to Bt-crops (termed refugia). Assuming resistance is caused by a recessive allele, refuge will ensure susceptible individuals are maintained in the environment because when a resistant individual mates with a susceptible individual, susceptible heterozygous offspring will be produced.  Further Considerations of Applying MCAs - Bt and baculoviruses are highly sensitive to UV radiation therefore it is necessary to use UV blockers. - When it rains the MCA is washed away therefore an adhesive must be used to stick the agent to the host plant. - To improve the performance of the microbe in the environment, the agent must be stabilised using chemical protectants, freeze-drying or encapsulation. Examples of Genetic Manipulation to Improve MCAs 1. Genes can be taken from an organism and put into a control agent to improve its efficacy. Genes coding for toxins that cause paralysis in insects for example have been taken from the predatory mite Pyemotes tritici and the scorpion Androctonus australis and put into baculoviruses which causes quicker death in the pest insect (Harper, 2006). 2. As well as adding genes, they can also be deleted in the control agent to improve its efficacy. The gene (egt) in baculoviruses for example causes infected larvae to cause more crop damage than uninfected larvae by delaying pupation thus giving the pest longer to feed. Deletion of this gene therefore reduces the damage caused by the pest and causes death more quickly (Harper, 2006). Genetic manipulation offers the potential to greatly enhance efficacy of MCAs by increasing the range of insects they target and decreasing the time it takes to cause death. Public and media opinion of genetically modified organisms however is highly negative and this has hindered progress (Nicholson, 2007).