PHYSICAL CONTROL IN

IPM

Submitted To :- Submitted By :- Dr O. P. Chaudhary Vaibhav Prof. of Entomology

PHYSICAL CONTROL -

Methods which aim to reduce thepest population by using deviceswhich affects them physically oralter their physical environment.

USE OF :

Temperature Moisture Light (radiations) Sound

PHYSICAL CONTROL

Temperature :

Artificial heating or cooling of stored products,grains etc. is a good method of pest control.

Low TemperatureHigh Temperature

Low temperature :

• Generally low temp. does not kill the insects, but slower down the insect activities

• Nearly all insects become inactive at 60-40°F.• Insects undergoes hibernation at 20 to 30°F.• Practically no damage occur from insects at temperature

below 40°F.• Low temp. is not as effective as high temp. in killing insects

but storage of food products and clothing, the temp. below or near the freezing point will prevent insect damage.

High Temperature :

• It is very efficient method to control insects.• No insect can survive longer when exposed to

temperature of 140-150°F.• Most of the insects (stored grains pests) can

be killed within 2-3 hours exposure to temp. from 125-130°F.

• In India and other tropical countries where the SUN is strongly radiant, solar radiation can be used for infected material like cotton seed, grains, pulses, woolen goods etc.

• Super heating with burning charcoal can also be used to raise temperature to destroy stored pest in godowns.

Steam sterilization

• Steam sterilization of soil is very effective against soil insects.

• Soil is covered with polythene sheet and steam is throwed on the soil.

Vapour Heat Treatment (VHT)

• When exporting tropical fresh fruit, such as mango and papaya, the fruit needs to go through strict plant quarantine inspections to ensure that quarantine pests such as eggs and larvae of Melon flies and oriental fruit flies are not present in fruits.

• The Vapour Heat Treatment System achieves this objective with the use of hot saturated water vapour, and without the use of any chemicals.

• During the process, the temperature and humidity are controlled so that the fruit is not damaged and freshness is naturally preserved.

• The Vapour Heat Treatment System is a safe way to treat fruit so that it passes the quarantine inspection, enabling the fruit to be exported.

• Heated air is saturated with water (>RH 90%) for specified period of 6-8 hrs. for raising pulp temp. to 43-44.5°C in case of mango against fruit flies.

OXYGEN STRESS

• In air tight containers small volume of air is enclosed, the available oxygen is quickly utilized by insects and raise concentration of carbon dioxide.

• High concentration of carbon dioxide leads to death of stored products insects.

LIGHT• Light affects insect behavior and development in a variety

of ways that can be divided into several categories.• One of the most typical responses to light is PHOTOTAXIS• Insects exhibit the following phototactic behaviors: Attraction Repulsion • There are a wide range of responses to light beyondphototaxis Light adaptation Circadian rhythms

Attraction • Positive phototaxis, moving toward a light source. This response can be used to trap pests, but the effective wavelengths and intensities

vary among species.

Repulsion • negative phototaxis, moving away from light this can be used to prevent pests from

entering a cultivation area by presenting light at wavelengths and intensities that repel them.

Light adaptation • when nocturnal insect species become light-adapted within several minutes of exposure

to and exhibit typical daytime behaviors such as cessation of movement and settling down.

• Behaviors such as flight and mating are inhibited in nocturnal insects that are exposed to bright light at night.

Circadian rhythms • are daily behavioral rhythms including flight, locomotion, feeding, courtship, mating etc.• Artificial lighting for a certain duration during the night can• shift the timing of the diurnal/nocturnal behaviors of This response is called a• ‘‘PHASE SHIFT’’

A - Attraction B - RepulsionC - light adaptation D - Disturbance of circadian rhythm

Light traps

• Light traps are arranged for attracting the insects, which are trapped by keeping water or oil in a container or a killing bottle below the light trap. Light traps are useful for monitoring the population of important insect pests in an area. Eg: Most of the moths and beetles.

RADIATION• Male insects can be made sterile by exposing them to GAMMA

RADIATION or by using chemicals. • When sterile males are released in normal population they

compete with normal males in copulation and to that extent reductive capacity of the population are reduced.

• By sterilizing the pupae of screwworm, livestock pest (Cochliomyia hominivorax) with radiations, sterile males were obtained.

• They were released @ 400/sq mile for 7 weeks. By this method total eradication was achieved in South East parts of America and in the Curacao islands in case of screwworm.

Flame thrower

• It is compressed air sprayer with kerosene oil for producing flames.

• There is a lance, which is fitted with a burner. When the burner is heated, the kerosene oil is released and it turns into flames.

• Used for burning locust populations, congregation of caterpillars, patches of weeds etc.

Kaolinic Clay (China clay)• is a clay mineral,• Chemical composition Al2Si2O5(OH)4. • It is a layered silicate mineral.• Used after successive activation with acid and heat can be mixed with

stored grains.• The clay minerals absorb the lipoid layer of the insect cuticle by which

the insects lose their body moisture and die due to desiccation.

DRIE-DIEConsists of highly porous, finely divided silica

gel.It abrades the insect cuticle.Loss of moisture from insect cuticle, causing

death of insect.Mainly used against stored product pests.