Measures to overcome low and high temperature stress

a. Cultural method

• Selection of frost tolerant variety
• Example: Mange:- langra, malda, Bombay green

Citrus:- mandarin orange, sweet orange, sweet lime, etc

• Planting wind breaks especially in north-west side of orchard
• Tender plants should be planted on the inner side of orchard
• Healthy plants are more tolerant to frost • Therefore, it is better to adopt good management practices to keep plants healthy

b. Mechanical method

• Heaters are used to raise the temperature of orchard in developed countries
• Heating by smoke: In this method, 8-10 fires per hectare of the orchard rises the temperature by ~5°C
• The smoke also contains the gas ethylene that promotes early flowering and fruiting in plants
• Covering by wrapping materials: stem is covered by straw or other dry material
• Using devices like plastic tunnels, hot caps and cold frames may help to reduce heat loss

c. High temperature stress

• This generally is accompanied by drought condition
• High temperature (44-54°C) injury to plants is often related to desiccation

Effects:

a) Sun-burn

• This effect is manipulated in leaves, twigs and fruits because of more transpiration

b) Sun scald

• Generally manifested in trunk
• It is the continuous drying of south-west part of trunk
• Tissues are dried of this part and brust

Methods to overcome high temperature stress

• Covering stem with wrapping materials
• Shading by constructing thatch- house
• Planting wind breaks for hot winds • Irrigation
• Use white washing, apply bordeaux paste on trunk