Protection of Crops

Insect - Pest Control
If insect pests attack the plant by cutting and destroying the root an insecticide like chloropyrophos is mixed in the soil to control it. If insect pests attack the plant by cutting the stem and leaves and it is a boring type of insect, it can be controlled by dusting or spraying contact insecticides like malathion, lindane and thiodax. If the insect pests sllck the sap from various parts of the plant, it can be controlled by spraying systemic insecticides like dimethoate and metasystox.
Disease Control
Plants often get infested with desease causing pathogens. The entire crop can be destroyed if they are not controlled in time.
Weed Control
Weeds are unwanted plants that grow in the fields where crops grow. The growth of weeds in fields has an adverse affect on crops because they compete with the crops for space, light, nutrients and water. The yield becomes poor and so also the quality of the crop. The weed could be another crop plant or a plant of another variety of the same crop. So if a mustard plant grows in a wheat field it has grown out of place and so is considered to be a weed. Often weeds harbour many insects, pest and diseases. Warm and humid climate being more congenial fo~ the growth of weeds, they are more during the Kharif season than the Rabi crop.
Based on the structure of the leaf, weeds are classified into narrow-leaf and broadleaf. The following are some of the weeds of the Kharif season and the Rabi season.
Kharif Season
Narrow Leaf Broad Leaf
Example: (1) Nutgrass (motha), (2) Wild Sorghum (Wild jowar) Example: (1) Amaranthus (chaulai) (2) Trianthema (Saathi)
Rabi Season
Narrow Leaf Broad Leaf
Example: (1) Phalaris (Mandoori), (2) Wild oat (Jangali jaii) Example: (1) Chenopodium (Bathua) (2) Convolvulus (Hirankhwci)
During Kharif season, short duration maize and millets, short statured groundnut and slow growing pigeon pea crops are more prone to weeds.
Methods For Controlling Weeds
Mechanical Method
Removal of weeds by mechanical methods are:
- pulling them out (uprooting) with hand
- removal by using a hoe or trowel
- interculture
- ploughing
- burning and
- flooding
Cultural Method
Cultural methods of controlling weeds include:
- proper seed bed preparation
- timely sowing of crops
- intercropping and
- crop rotation
Chemical Method
Spraying of specIal chemicals called weedicides or herbicides is a chemical method. Example: atrazine; 2, 4-D, fluchloralin; isoproturon
Biological Method
The biological method involves the use of some appropriate insects or some other organisms on the ,crop field having weeds. They selectively destroy the weed plants but do not harm the crop plants.
Example: Cochneal insects are used to eradicate opuntia (a weed, commonly called prickly pear). Aquatic weeds are controlled by grass carp (a kind of fish).