Integrated Insect Management: Philosophy and Impact
Mazhar Hussain Ranjha
The basic role of knowledge has always been to improve the efficacy of existing options for the solution of a problem and to introduce more alternatives to ensure the existence of an organism. This hypothesis can be practically tested for all living organisms and the diversification of its results would depend on the potentials of an organism to recognize the existing or coming threats and to interpret his previous knowledge and cognitive capabilities to overcome the problems.
The interaction between man and insects has a long period of age and both of them have learnt a lot to deal with each other. Interestingly enough, they both have got similar “basic necessities” of life and the existence of one is a threat to the peaceful and comfortable survival of the other. In order to face this problem man has devised many strategies to combat with insect from time to time. During the birthdays of civilization, entomophobia (fear from insect) and some other economic coercion motivated him to eliminate the insects from this planet, the Earth. But due to the texture and size of insect body, reproductive potential, capability to flight, adoptability in new environment and their diversity discouraged this idea. Then man kind had a single option and that was that to have a compromise with their foes and to be contented to think of that insect should be kept below a level which was later on entitled as ETL (Economic Threshold Level).
Anthropological studies help us to know the ways adopted by our forefathers to check the insect populations. Some records reveal that many ritual festivals were celebrated in order to get rid of insect. Even religious slogans were chanted along with some holy words or signs near the crop area and dwellings to protect them from the evils of insects. With the passage of time, some plants were observed very effective against the insect pets and the cuttings of different parts of these plants were scattered in the vicinity of valuable articles. In some area of the world these plants got a sacred status and they were worshipped due to their socio-economic value. Later on the discovered plants were tested and the botanicals were extracted from them which are still in our use for crop protection. Actually health and safety of livestock, protection of residential areas and promise of “food security” to feed the increasing population of human beings opened new horizons of discoveries in both tools and strategies right from the discovery of botanicals to the latest insect biotechnological aspects of IPM (Integrated Pest Management).
Now a days we are interested in to incorporate and integrate all existing options to fight against insect pests because if one method is failed, the other should be there to compensate the first one and so on. Similarly, if all methods are utilized the net result would be better than employing only a single operation. This logic is also supported by the existing scenario of the world in terms of its food security. We can not put our crops on the fate of insect attack because the boom in population of human race needs more food security.
In order to get the empirical results of Insect Pest Management, the basic knowledge of insect physiology, morphology, ecology, taxonomy and biochemistry etc., is essential. The complete bio-data of insect pests explores the vulnerable stages of insect life, optimum temperature and humidity for their control, their behavior of oviposition etc. Comprehensive information about the insect life history helps us to develop a strategy against it otherwise we would be like an army going to fight against another army about which it does not know a single piece of information about its weaknesses or strength.
There are several tactics which exhibit prime importance in Insect Pest management. The first one is to save our energy and inputs when insect density is below ETL. For this, regular monitoring of crops to take notice of the insect population is recommended. The other one is to plant insect resistant varieties which would fight our war against insect pest. In addition to above mentioned tactics we must deal with insect by keeping in mind their status. Major, Key and Severe pests are first priority to control in comparison with minor and occasional insect pests.
The methods mostly employed for insect pest management in a compatible manner include cultural control, biological control, induced disturbance in behavior of insect, chemical control, sterile insect technique and genetic control. Each of these methods is discussed separately for their brief introduction but all possible techniques among these should be hired depending on the economic, ecological and insect pest nature.
In the case of cultural control, it includes the practices on farm right from the seed bed preparation to the maturity of the crop. Among these practices, ploughing, hoeing, removal of weeds and animal wastes, irrigation are useful to discourage insect pest spread. On the other hand, crop location, crop rotation, tillage operations, introduction of trap crops etc., also support the cultural control. This control method plays both short term and long term role in insect pest management and it has biforked role in crop production as well as in crop protection.
The biological control engages many biological elements which perform their natural duty in the ecosystem to maintain the natural food webs and food chains in ecosystem. In addition to natural role of these elements like parasites, predators, pathogens, we are interested to rear them, introduce them and then test their efficacy in field. An environment of support for these useful agents is produced to sustain the role of biological agents without any interruption.
The biological studies of insects reveal that there are many hormones in them which cause normal growth and development of them. In order to control insect pests the hormonal role is disturbed and ultimately the insect are died off or they get “unfit” for their performance. By knowing the behavior of insect in their daily life many attractants and repellants are introduced to check their population. Disruption in mating behavior plays a key role as it reduces the next progeny of the insect pests.
A good number of chemicals (insecticides) are used to kill insect pests. The chemicals should be used on proper timing and with recommended dose for each type of insect pest mentioned on label. Unwise usage of insecticide is very dangerous because it may enhance insect resistance and outbreak of insect pests.
Many transgenic crops are produced who’s physiological and morphological characteristics make them unsuitable to insects and their role of causing non-preference and their nature of tolerance and resistance secure the crop from the insect pests. Biotechnological advancements have brought mutation in crop and these crops have dual role; primarily they act as a crop and their secondary role is to act an automatic pesticide. The insect pest who eats these crop parts is killed by the pathogens introduced in these crops by biotechnology.
The ancient idea to eliminate the insect pests from planet is still related with Sterile Insect Technique. In this technique both male and female are sterilized but mostly male is sterilized in cases where the counterpart female mates occasionally and lays a lot of eggs. This technique is very expansive and laborious one. Radiation and chemosterilization are used to make them sterile. Then the population of the sterile is produced in a large number so as to assure the competition with the wild insects. It is much more useful when it is practiced with safe chemicals.
In the case of genetic control, mutation and genetic variations are brought in insects to make them unfit for survival.
Our farming community is not well educated and the case studies of integrated insect management are not encouraged on merit. The demand of the age is to control insect pests in such a way that should be environment friendly and effective for sustainable crop production. Otherwise we will keep on producing huge bulk of crop produce with lowest prices in international market. So, it is necessary to change the psyche of farming community by introducing alternative methods and their compatible application after sound research findings feasible to our ecological conditions and acceptable to our farming community.