Welcome to this channel! Hello everyone! My name is Zohir Chowdhury.
So today we will discuss about methods of pest control and pesticide resistance.
as we talk about method of pest control uh the main thing that is applied in agriculture is
integrated pest management or ipm and so the goal of integrated pest management or ipm is to control
pests not to eliminate them by using a variety of methods to keep each past population just below
uh the size that causes economic loss and in fact in here you can see that here you have a pest
population that is steady states going up and down uh by using integrated pest uh control uh system
you can reduce this pest so that it is uh lower so that uh it is below the uh economic threshold
so you can still make significant money uh out of um your crops but the pests are not fully
destroyed from the ecosystem and that helps to avoid resistance which we'll talk later
um so each crop and its best are evaluated as parts of an ecological system
and control program developed include a mix of cultivation practices biological
methods of pest control as well as chemical control methods as well
so in here uh we can see some of the uh ipm uh methods of pest control so many tactics keep
pest population off balance and avoids development or resistance to pesticides least toxic effective
methods are used before more toxic ones whenever possible the goal of using multiple tactics or
small like many small hammers is to effectively suppress paths below injurious levels and avoid
outbreaks so the first types of practices are listed in here which is cultivation practices
the goal in here is to suppress pest problem by minimizing the conditions they need to leave so
that the the water the shelter the food you're trying to minimize uh those um so the pests cannot
like they don't like it over there so planting plants that are adapted to your
growing conditions as well as planting them in the right place are also very critical so that the
plant can actually thrive and fight past by itself as well strong plants
a plant resist diseases outgrow weeds and are less likely to succumb to
insects other cultivation practices could be rotating crops every year planting trap
crops to lure past away adjusting planting times into cropping as well as polyculture
beside cultivation practices you may also employ physical methods as well so prevent pest access to
host or area or if the pests are already present in that area physically removing them by some
means for example this could mean using barriers scraps vacuuming mowing or tillage depending
upon the past and the situation that arises there you could also use genetic methods so i use pest
resistant plant varieties developed by classical plant breeding recently this category has been
expanded to include genetically engineered pest resistance there are also special uses of genetic
techniques on pests themselves such as sterile male insect release and what that means is like
you have this male population that are sterile and they are there and they cannot reproduce
so once they mate they don't have additional pests in the ecosystem anymore um biological uh
control methods are also quite popular so use predators parasites and diseases of pests
in a targeted way to suppress pest population use of microbial diseases of pests have become part of
the chemical pesticide registration process and is treated below under chemical methods
uh use of predators and parasites as biocontrol for pests are handled in one or more of three ways
so um one method is conservation uh and encourage and encourage encouragement of naturally occurring
biocontrol organisms by cultural techniques or at least or at least avoidance of harming them
number second is augmentation of naturally occurring species by purchasing and releasing
more of the same and number three is classical biological control in which new biocontrol
specific to pests are sought and introduced in the field um the chemical methods on the other hand
there are quite a few and are used that are used in pest management situations but not
all chemicals are alike from the standpoint of their range of action toxicity or persistent in
the environment so conventional method can also be utilized conventional pesticides currently
referred to synthetically produce compounds uh that acts as direct toxins such as nerve
poison stomach poison etc so you inject you are releasing these specific pesticides in the field
um to control pests and that's a conventional method and there are
of course many classes of chemical pesticides um that can be utilized in here in addition
regulatory methods are also quite effective regulative control refers to the role played
by government agencies in trying to stop the entry or spread of pests into an area or into the
country via inspection quarantine destruction of infested material and other methods and typically
this happens in various port of entries such as airports or other port of entries into the nation
so finally the topic of pesticide resistance are shown in here so resistant to pesticide resistance
to pesticides is a serious and growing problem worldwide more than 600 species of pests have
developed some level of pesticide resistance if resistance to a particular pesticide or family
of pesticides evolved these products can no longer be effectively used thereby reducing the options
available for pest management resistance is defined as a change in the sensitivity of
a pest population to pesticide resulting in the failure of a correct application of the pesticide
to control the past resistant can develop when the same pesticide or similar ones with the same mode
of action are used over and over again it often is thought that pests change or mutate to become
resistant however it is not the individual past that changes but the population when a when a
pesticide is applied to a crop or a treatment site a tiny proportion of the pest population
for example one insect or wheat in 10 million may survive exposure to the pesticide due to its
genetic makeup when the pests that survive breed some of their young will inherit the genetic trait
that confers resistance to the pesticide this past will not be affected the next time a similar
pesticide pesticide is used in the same place if the same pesticides pesticide is applied often the
proportion of less susceptible individuals in the population will increase when the pesticide decay
applicator recognizes that once highly effective pesticide no longer control the pest at the same
rate higher rates and more frequent applications become necessary until eventually the pesticide
provides little or no control the population may then be said to have become resistant
by illustration on the right well on the on the on the left in here it shows how a resistant weed can
dominate a field treated with the same herbicide year after year after year the green symbol
uh represent the wild type uh uh or susceptible wheats and the red or orange symbols represent
uh the resistant ones you know if a herbicide is applied in this first year it would kill the
susceptible plants but miss the few resistant ones this will result in in good seed production from
the resistant plants but little seed production by the susceptible plants as a result there's
a small increase in the percentage of resistant plants in year two as you can see in here if the
same herbicide is applied once again there'll be a few seed produced by the susceptible plant but the
resistant plants will continue set to set seeds this result in an increase in the percentage of
resistant wheats in year three with the repeated use of the same herbicide there is a greater
increase in the percentage of resistant weeds with most of the population resistant by
year four and five although the genetic factors may differ among pests that have become resistant
all cases of resistance are driven by this process of what is called natural selection
so with respect to resistant management ipm is definitely a good technique so growers
can help delay the development of resistance by applying pesticides only when they're needed by
rotating between different chemical classes and by using rates of pesticides within the label range
uh integrating non-chemical approaches such as pheromone-mating disruption and cultural control
as mentioned earlier can also delay the resistance of pesticides well thank you for listening
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