Physical control

Physical plant protection measures include the application of low and high temperature, irradiation, high frequency sounds, light, carbon dioxide, ozone etc., and visual and olfactory baits that cause a reaction of pests to certain stimuli. These measures are used more in insect control than in disease control. The most commonly used are:

• high temperature for thermal soil disinfection. Destruction of harmful microorganisms, pests and weed seeds is achieved by heating the soil to 95 ° C to a depth of 30 cm for 5 minutes;
• solarization or use of solar energy, is a very effective measure for soil disinfection, and is carried out by covering the soil during the summer with a thin, transparent, polyethylene foil for 1-2 months;
• differently colored adhesive boards (sticky traps) attract pests that stick to the adhesive surface. In this way, the attack can be reduced and the number of pest populations can be determined, as well as the beginning of control. Yellow sticky traps that attract aphids and moths, and blue sticky traps that attract thrips are most commonly used in the protected area. In fruit growing, yellow traps are used to attract cherry and olive flies, while white traps attract wasps and red bark beetles;
• light traps can be used to determine the presence and thus reduce the insect population on agricultural land and in warehouses. They are used to catch moths such as armyworms, cutworms, stem borers and other night flying insects. However, light traps have the disadvantage of attracting a wide range of insect species. Most of the attracted insects are not pests. In addition, many insects that are attracted to the area around the light traps (sometimes from considerable distances) do not actually fly into the trap. Instead, they remain nearby, actually increasing the total number of insects in the immediate area;
• reducing the humidity and temperature of stored agricultural products in silos;
• controlled atmosphere in refrigerators for fruit storage. Carbon dioxide is toxic to insect, but its action is low. Eggs and adults of pulse beetle die when exposed to 100% CO2 at 32°C and relative humidly of 70%. Carbon dioxide under high pressure is found to be effective against stored grain pests. Carbon dioxide and nitrogen treatment have been found effective for grain beetle. A nitrogen atmosphere effectively controls all stages of fruit fly;
• irradiation (microwaves and gamma radiation) are being used against stored grain pests effectively. Infrared radiation can be used dually to the insects or to the stored grain infested with insects. Ionising radiation (X-rays) are sterilizing at lower dosages but lethal at higher dosages;
• sound - low frequency sound waves cause adverse effect on development of insects. Sound produced by male and response of female of a species to the sound can be utilized for their control.