The tea growing environment in the North East India is conducive to a large number of pests and diseases. Detail studies have been made at Tocklai on the biology and control of tea pests during the last decades. Adequate and timely measures are to be taken to reduce crop loss due to pests and diseases. Pesticides invariably leave residues and their indiscriminate use may render the teas unsuitable for consumption and trade. With ever growing concern over pesticide residues and the rising costs of the pesticides, the concept of pest control has undergone radical changes. Therefore, monitoring of pests for their early detection, integrated management of pests (IPM) and discretion on the choice of pesticides to be used on tea is of utmost importance.

The major pests, their site of attack on the tea plant, the period of occurrence in North East India, their mode of dispersal and some of the alternate hosts are shown in the following table.

Mode of dispersal of some major tea pests

Important weed hosts of tea pests in North East India

Cultural operations :

1. Bush sanitation/Cold weather practices
2. Ground sanitation
3. Balanced nutrition
4. Soil rehabilitation prior to replanting.
5. Improved drainage
6. Proper shade management
7. Soil amelioration

Mechanical and Physical Methods :

1. Hand collection
2. Light trapping

Regulatory Methods :

Only healthy, pest and disease free planting materials should be procured/used.

Biological methods :

Biological methods of control involve the conservation, preservation and introduction of natural enemies of tea pests, like predators, parasitoids and pathogens for suppression of pests within tolerable levels. More than one hundred indigenous natural enemies (predators, parasitoids and pathogens) have been recorded against various tea pests. A list the identified natural enemies against their respective hosts are given in the table below:

Some common indigenous natural enemies of major tea pests

Pesticide can have detrimental effects on natural enemies thereby disturbing the bio-diversity and the balance in natural ecosystem. It is therefore necessary that the indigenous predators, parasitoids and pathogens are adequately preserved. Less toxic, selective pesticides should be preferred as much as possible, to keep the natural enemies active in tea areas.             

Chemical control & Choice of Pesticides

TRA has organized awareness campaigns among the tea planters of this region through seminars and conferences highlighting the need for safer plant protection schedules for minimizing residues so that tea continues to be a health drink. TRA has also generated data on residues of commonly used pesticides in tea through extensive supervised field trials. A number of invoice tea samples have also been monitored for pesticide residues recently, which reveals that most of the samples have residues well below the MRL limits.

Steps to minimize pesticide residues in tea

• Monitoring and early detection of pests
• Integrated pest management
• Use of safer pesticides, botanicals and bioagents
• Avoid repeated spraying of the same pesticide
• Allow sufficient waiting period between spraying of pesticides and plucking
• Spot treatment

Pesticides approved for use in flushing and non-flushing seasons

Diseases of Tea