Biological Control of Tea Pests

Introduction: In Tea Garden, there are many tea pests, which are very familiar to us and we go behind them after spotting, they largely affect the crop. There is a natural army against them If it is available in the Research paper then difficult to understand by many people. Since I did my education from Tamil Nadu Agricultural University, Madurai campus under the best of Entomology Professors, I had a thought to compile them all and make it simple and easy to understand. I started observing Tea garden predators from 4.5 years back and decided to document them in Photographs and Videos, after so many years, Now I am bringing them all together for a better understanding of Predators. Tea Garden predators may be specific to a certain location and vary from garden to garden but some species viz. A ladybird beetle, Greenlace wing Larvae, Assasin bug, Shield bug, Spider ( Species may vary garden to garden), Ants, Preying Mantis, Ant Mantis, Birds (Species may vary), Lizard, etc. are commonly seen in all the garden. This article will summarize a few of the Predators' details which may be helpful to understand the role of natural control. I will also seek useful comments at the end to know more about the predators of other Tea Garden. This is based on my observations and documentation at Nonaipara Tea Garden. I got the opportunity to go closer and observe them minutely. There are more than 30 species of Spiders in the garden, which keep check on pest increase. They basically feed based on their sizes on pests like Helopeltis, Greenfly, Looper moths ( All based on my observation). Most of the spiders are predators that feed on insects and even other spiders, they only feed on live prey or prey that they have recently killed. The spiders bite the prey, wraps it in silk, waits for it to die, then begin to eat. As the first step in eating, the spider will literally vomit digestive fluid over the prey. Then the prey is chewed with the "jaws" (chelicerae), and the fluid is sucked back into the mouth together with some liquefied "meat" from the prey.

In the book "Living in the Environment" by G. Tyler Miller, Scott Spoolma They have mentioned that The Natural ecosystem services are an important part of the earth's natural capital. For eg- world's 46,700 known species of spiders kill far more crop-eating insects every year than humans do by using insecticides.

Natural control is "the maintenance of a more or less fluctuating population density of an organism within certain definable upper and lower limits over a period of time by the actions of abiotic and/or biotic environmental factors" - B. P. DeBach (1964).

Why biological control?

1. Highly economical
2. Selective with no side effects
3. Self-propagating and self-perpetuating
4. Pest resistance to BCAs is virtually unknown
5. No harmful effects on humans, livestock's and other organisms
6. Virtually permanent ? Efficiency, greater ability to search their prey
7. Improved quality of produce
8. Compatible with most of the IPM components

Biological control is "the action of parasites, predators, or pathogens in maintaining another organism's population density at a lower average than would occur in their absence".

Natural biological control as that "control that occurs without man's intervention"

Three approaches to biological control

1. CONSERVATION OF NATURAL ENEMIES: Actions that preserve and increase NE by environmental manipulation. e.g. Use of selective insecticides, provide alternate host, and refugia for NE.

2. CLASSICAL BIOLOGICAL CONTROL: The control of a pest species by introduced natural enemies (Mainly to control the introduced pest)

3. AUGMENTATION OF NATURAL ENEMIES: Propagation (mass culturing) and release of NE to increase its population. Two types, (i) Inoculative release: Control expected from the progeny and subsequent generations only. (ii) Inundative release: NE mass cultured and released to suppress pest directly e.g. Trichogramma sp. egg parasitoid, Chrysoperla Carnia predator.

Greenlace wing larvae actively feed on many tea garden pests, which is many times larger than its size. They mainly feed on Scale Insects, Aphids, Thrips, and Greenfly.

There are however many bugs that are important predators of other insects. They range in size from the minute Orius to the ferocious Assassin bug.

These stealthy predators feast on live insects, including moths, mosquitoes, roaches, flies, and aphids, as well as small rodents, frogs, snakes, and birds.

It is very important to know the eggs of predators and how to save it till hatching. In the tea garden, I have observed that spiders are fast enough to construct their web ( House) if they get damaged by pluckers, sprayers, or any other operations in the garden but the others eggs of predators viz. Bugs, Mantidae, Lacewing, etc. once damaged will be destroyed forever. So, understanding and awareness about predators will help us prevent them and make the garden more sustainable.

Assassin bugs are predatory insects, and beneficial for the garden, control is not recommended. Assassin bugs, including wheel bugs, are generally not very abundant and do not require insecticidal sprays. They are true to their name, these tiny ninja warriors prey on the enemies of precious plants.

It is more important to identify and make a difference between predator and Pest eggs. There is also a lack of awareness between the garden workers, who find any insects as a Pest. An insect may be a pest or predator, it depends on the crop. In tea garden scale insect in as pest but it is used to control invasive species of prickly pear, which spread widely in Australia and Africa.

Birds as a Predator? Have you ever wondered what they do eat?

The main reason, I am sharing is to "Alone we can do so little; together we can do so much." Please share your opinions, work, your views on above to make it available to many people and create awareness to save our Natural guards.

Thanks, I can reach out at [email protected]

There is also a video link below on Predators in Tea Garden