Limitations or Disadvantages of Microbial Control
1) High Selectivity/Host Specificity:
Since the microbial agent is effective against only single pest species there is a very limited market potential.
2) Requirement of Additional Control Measures:
An additional control measures are needed for non-target insect pest species. It present and not kept below ETL by natural control factor.
3) The Correct Time of Application:
In this respect, the incubation period of disease, which is a critical factor and difficult to judge because of age specificity and stage specificity. The pathogens attack on certain stage (larval) and do not produce effect on eggs or adults. Susceptibility of larvae also decreases with increase in age.
4) Delayed Effect/Mortality:
The pathogens require some time to produce response in their target host owing to its long disease incubation period.
5) The pathogens like viruses, bacteria must be ingested as early as possible to produce effects, while the fungi required entry through body integument for which good coverage of spray deposits is important.
6) Storage Problem:
It is necessary to maintain the pathogen in viable condition. Even average temperature and sunlight degrade the microbial preparations. Exposure to sunlight causes UV radiation and losses its virulent immediately. The pathogens have very short self life.
7) Difficulty of Culturing in Large Quantities:
Rearing host insect on artificial diet is more cumbersome and laborious works which requires constant supervision. The whole organisms techniques for in vivo prorogation of virus are fairly labourious and expensive.
8) Short Residual Effectiveness:
This is the major limitation absent the effectiveness of pathogen under field conditions as sunlight causes UV radiation.
9) Not legally protected and data needed for registration is highly expensive.