 Hi, welcome back to the course on integrated pest management. In the last few classes, you understood about some of the components of IPM such as the ecological means of pest management, host plant resistance, etcetera. Now, in next few classes, let us understand the another important component in the integrated pest management that is biological control. So, what is biological control and what the history of biological control a little bit of it and the concepts of biological control and some of the important biocontrol agents such as predators, parasitoids or the microbial pathogens, the advantages and limitations of biological control and how these biological control program can be integrated into the IPM or the activities or the lectures that we are going to deal in the next few classes. Now, so what is a biological control? It is quite essential like or it is quite common that all of us know about the biological control. Since time immemorial, so the people are using this biocontrol program in their daily life. One classic example that I can give is like we all rare the cats in our houses in order to control the rats. So, similarly for the insects which causes the economic damage to the crops in an agricultural ecosystem can also be controlled by using some other insect groups or a non insect groups and keep their population at a lower level. So, how you can actually define a biological control is the action or the activity of the predator, parasites or the pathogen. So, which actually keeps the pest population density at a lower level with this graph we can even understand better. Here we all know about the general equilibrium level of the pest and we know that whenever this general equilibrium position of the pest will goes beyond the economic threshold level then it becomes pestiferous. So, at this point when you actually introduce a natural enemy then what happens? These natural enemies act upon the individuals of these pest and then they bring down the population and make it into an a modified equilibrium level which will be normally below the economic threshold level. So, our main aim here is to bring down the population at a lower level. So, below it actually causes the economic injury level. Why do we need the bio control? So, if you look at some of the points that I have mentioned here. So, it is highly economical in the sense like with a very minimum expenditure then we can get a very big or good management and it is quite selective with no side effects. So, that means some of the biological control agents are quite specific to certain pest and they do not actually leave any side effects in the environment and they are self propagating and self perpetuating this is quite important like once we actually release or conserve these natural enemies then they are going to remain in that habitat for a longer period as they keep multiplying on the pest and then keep controlling it. Then the pest resistance to the biological control agents is virtually unknown that means there is no problem unlike in chemical means of management where the insects are known to develop the resistance against the bio control agents there are absolutely no report except in some pathogens we do have and there are no harmful effects on the humans, livestock and other organisms. So, the non target organisms are quite safe and they are quite permanent virtually permanent we can say that they exist in that habitat and the efficiency and there is a greater ability to search their prey. In this case so, just we can release at one point and these bio control agents some of them like predators and parasites can go in search of the prey and then control them and there is an improved quality of the produce the what is called as the residual toxicity or some kind of those problems will not remain in this kind of the program and they are quite compatible with most of the IPM components. Now, if you look at the history of a biological control program so, we can actually look at it has got a very long history and wherein somewhere in 900 AD so, the people will use to use some of the insects such as the red ants like Oecophila smaragdina in order to control certain mealy bugs or the scales in some orchards. So, this has been a well classified or a well recorded a document, but there is a one example that I will give which actually lead to a classical biological control and this actually gave a global attention about this phenomena. So, during late 1816's there was a pest called as a cottony cushion scale or Isaria Parchegi which was somehow introduced to California state and it colonized on the citrus plants and within few years it multiplied in the absence of the selection pressure such as its natural enemies to such an extent that it started causing a huge economic loss. So, when the scientist started looking into the biology and as well as the history of this pest then they came to know that this is not a local pest. So, this is an exotic or a introduced one. So, the best way of controlling this would be to search some natural enemies in its place of origin. So, as a result when they traced back the place of origin of this pest they found that it actually was introduced from Australia and upon close observation of some of the local natural enemies in Australia then they selected a lady beetle which is called as Rodelia Cardinalis and they brought few individuals of this Rodelia beetle or Rodelia Cardinalis and then released in the California state on this pest. Within few years so they got a spectacular control and this has actually led to believe in the capacity of the biocontrol agent. Similarly, in India also we do have certain examples of classical biological control and now we shall look into it. In India during 1926 the same cotton equation scale that is Isaria Parchegi was quite serious and in order to control this the same beetle that is Rodelia Cardinalis was introduced. Then during 1941 there was a serious plant that is an what is called as a Lantana camera which become a quite serious weed in India and in order to control this weed the tingeed lace bug that is Tilonomia scrupulosa was introduced and it is keeping this weed in check. In 1951 again another lady beetle that is Cryptolimus Montrezeri was introduced against mealy bugs. Then in 1982 so there is again another water weed which is called as a water hyacinth and this is quite serious problem and in order to control this so three exotic natural enemies were actually brought that is two weevils Neocartina's Brookie and Neocartina's Iconia and a mite so which actually are keeping this weed under check. Similarly, in 1983 and 84 there was another water weed which is a Salvinia molesta and in order to control this so they brought another exotic weevil that is the sea Salvinia and this is also doing a good job. Similarly, in 1983 again so they actually imported the parasitoid leptomastix Daxillopi in order to control the planococcus citri amelipug. Then we all know that the what is called as ill hazards of the Parthenium weed and in order to control this the chrysomelid beetle zygogramma bicolorata was introduced during 1983. Similarly, in 1988 so another coxinated predator that is Curinus Curilius was introduced in order to control the heterosylla Cubana that is the Subabul cilid and most recently we know an example during 2010 that is where the papaya amelibug has started creating a havoc in southern states of India and by introduction of the parasitoids like acerophagus papaya and others so we got a good control of these pests. Now what are the approaches of the biological control like there are three major approaches in biological control where in depending upon whether the pest is a localized one or it is an introduced or an exotic or how fast that we need to control the pest in case of say annual crops so we need to control it quite quickly whereas in case of perennial cropping system so we need to make that natural enemy to establish in that ecosystem with an inoculatory lease. Let us look at some of the important approaches which we actually employ in biological control program. So the first approach will be the conservation of the natural enemies so this suits well when we are actually dealing with a local pest since the local pest which is already there and which has its origin here itself so in such cases we normally get the natural enemies within that ecosystem only maybe because of some abiotic or the biotic factors it might have actually raised to the pestifera level in such conditions we have to create a situation wherein the natural enemies of that local pest should be conserved and so the pest population can be actually put below the economic level. So how do we do that? So for example by use of certain selective insecticides or the management practices which do not harm or eliminate these natural enemies so that the natural enemies will thrive and they start actually controlling the pest or you provide certain alternative host or the refugee of other natural enemies so that they can actually escape and then again come back and then cause the what is called as control the pest population. The second approach is a classical biological control so with one example that I have already explained and this type of control mainly holds good when there is an introduced or an exotic pest. So this normally we do it by introducing the natural enemies from the place from where the pest has actually been originated. So the third approach is the augmentation of the natural enemies in the sense like based on how quickly that we need to control the pest then we go for two types of approach one is an inoculative release and the second one is an inundative release. In case of inoculative release what we do is we only release the few individuals or a smaller colonies of the natural enemies so that they actually sustain and then subsequent generation they actually control the pest. This actually we do it in an what is called as a more or less permanent ecosystems such as an horticultural ecosystem. In case if the crop is quite short duration and if we need to control the pest immediately then we actually go for inundative release. In this inundative release we must multiply the natural enemies under artificial condition and then release into the field which actually suppress the pest quite quickly. Now under the classical biological control so certain procedures we need to take up because we are actually dealing with an introduced pest. So what are the steps to be taken in the classical biological control? For example we have to actually first evaluate the pest problem we should know that what extent the pest problem is there and then you go for an foreign exploration that means try to identify the natural enemies from the place where this pest has originated surely we are going to get and then select one or two important natural enemies or which are quite potential there and then you actually complete the process of quarantine and bring here and then go for mass propagation. Standardizing a mass multiplication technique is quite important then after producing it in large number then you release them in the field and then see that they are actually colonized. Then once they are colonized then periodically we should keep seeing or evaluating the impact of that natural enemies on the pest and also taking in view that so that natural enemy should not create a problem in this new ecosystem. So there are three major biocontrol agents that I was mentioning which play a major role in this biocontrol program. So one such agent is the predator. So let us now look at what is a predator and what are the important groups of predators. So the predator is an any animal that feeds upon the other animals which we call it as a prey that are either smaller or weaker than itself and this is quite a general example or the definition we can say. So what should be the character of a predator if you actually look at it so if when you are selecting any predator it should fulfill certain characters like it should be quite active and it should actually has a good host searching ability and should be a very voracious feeder that means in both like the immature stage and the adult stage if it is in a feeding actual feeding stage that is quite good and also it should always found in a closer vicinity to the prey. Now some of the potential predators if you look at for example the lady beetles the lady beetle which belongs to the family coxinaliding under the order colioptera is very popular and very effective predator. So most of these lady beetle species have already been employed in the biological control program. Basically these beetles feed on soft bodied insects such as aphids, scales, millibugs and eggs of the some of the leopard optrines. They are quite voracious and most of their immature stage and as well as adults are actually the active feeders. Some of the examples like cryptolimus montregeri I already told you. Rodelia cardinalis is one of the example for classical biological control. Come local predators like the coxinalus septum punctata, coxinalus sex maculata and skimnos coxiora are also quite effective. Similarly we have a tiger beetle which is scindella sex maculata is also quite general predator and carabids like anthia succicata and these are quite general predators. So dragon flies we know they also feed on some small flies including mosquitoes and give a better control. Apart from that some flies are also there like the robber fly and as well as the hover fly. Then under neuropteran order so we do have a green lace wing. The green lace wing is also quite efficient in controlling the soft bodied insects and the eggs of certain pests. So the standardization of the mass production technique has also been done that. Under bugs or hemipteran condition we do have a citronus levidipenis which is quite effective against the hemipteran bugs especially the brown plant hopper and under leopard also we do have certain predators like defy ephedivora and a brown lace wing micromasigoratus is also a quite effective predator. So these are some of the important groups of predators so which are normally employed in the bio control program. So how they have been actually employed in the bio control program. So some of these predators their doses has been standardized and the target host is also been standardized. Say for example tryptolimus montryseri agonist mealy bug it is recommended to release at the rate of 3000 to 4000 adults per hectare. Similarly rhodelia cardinalis and as well as the chylochorus negrita. Then in case of the chrysoprolacarnia that is a green lace wing so about 1 to 1.5 lakh grubs of the eggs per hectare is been recommended and also the defy ephedivora another predator on sugarcane woolly ephed around 5000 to 6000 per hectare has been standardized. So if we mass multiply and then release at an appropriate time so then they keep these pests under check and below the economic injury level and form a very good component in the integrated pest management. So in the next class let us look at the another important bio control agent that is a parasitoid and their classification and as well as their potential in the bio control program. Thank you.