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Chapter 6 - Plant protection practices

Ploughing, hoeing and basin preparation
Hand picking of pests
Cow-dung and clay mixture
Pruning of fruit trees
Use of wood ash on and around vegetable crops
Beating drums and using domestic dogs for combating the menace of birds and monkeys
Kerosene oil for killing borers
Use of walnut and swetflag leaves against pests in stored grains
Indigenous beekeeping practices

In recent years, the large scale application of pesticides, primarily insecticides, has made cultivation of some mountain crops and fruits difficult due to the harm brought to bear upon the bio-environment by large scale destruction of natural bio-enemies causing pest resurgence, development of resistance to pesticides and consequent secondary pest outbreaks. Perhaps the only solution to this problem at hand lies in the adoption of eco-friendly approaches which are not destructive to natural enemies but gradually remove sizeable proportions of pest populations and tend to keep their populations in check. Physical, (devices and procedures used to change physical environment of pest populations), and mechanical (mitigating pest populations by cultural practices) methods of pest control are the oldest of all such insect control methods. These are rooted in simple practices that man, as a farmer, has leant from his long and close association with pests. These aid him in reducing pest populations to low levels. These include both direct and/or indirect measures which may be preventive or corrective in nature but are essentially slow acting, often ecofriendly, cost effective and compatible with other methods of pest control. These characteristics make them amenable to blend better with integrated pest management practices (IPM) even though they do not bring about an immediate or drastic reduction in pest populations. Even the modem concept of pest control does not emphasize the outright eradication of pests but focuses on maintaining their populations at levels which do not cause economic losses. Some of the indigenous methods of IPM include:

Ploughing, hoeing and basin preparation

Cultural practices like ploughing, hoeing and basin preparation influence directly, the survival of soil inhabiting pests. These routine agricultural operations expose soil inhabiting insect, pests and other arthropods and nematodes to harsh weather and to natural predators. Insects are most vulnerable when in the pupal stage and most insect-pests pupate in the soil which furnishes a protective habitat. Birds like the king crow, the myna, the starling, etc. pick up the exposed pupae following these cultural operations. Some insects e.g. grasshoppers, crickets, mole-crickets and borers lay then-eggs in the upper layers of the soil. Their eggs are exposed during soil preparation and subsequently desiccate. Many insects like cutworms, grubs of the root borer and white grubs which feed on the root system of plants are also exposed to the vagaries of the elements during basin preparation and hoeing. Deep ploughing carried out during winter helps in reducing the overwintering populations of several pests.

The afore mentioned cultural operations are performed manually in the hills using locally made tools and implements discussed in chapter 9.

Beside dislodging the pests from their protective habitat and subjecting them to unfavorable conditions for survival, these scientifically tempered cultural practices also improve aeration of the soil and facilitate proper percolation of water into the soil.

However, the degree of success of these operations is related directly to the presence of natural predators in adequate numbers and the synchronization of these operations with the vulnerable stages of the pest's life cycle.

Hand picking of pests

Hand picking of pests and their destruction is another time tested method of pest control. Right from picking lice from human hair, clothes and even animals to the manual separation of pests from stored grain. This method can prove effective in curtailing pestilence on some crops. Insects which lay eggs in conspicuous and easily eliminated masses, e.g. tobacco caterpillar, gypsymoth, hairy caterpillar, sugarcane top borer, epilachna beetle, etc. can be easily eliminated. Early instar larvae of such insects often feed in congregations and later disperse on to the entire plant/tree and in the field, making control, at best, difficult.

Hand picking demands alertness, patience and keen observation. The collected pests are destroyed by immersing them in kerosinized water or by deep burying. Nocturnal insects responding positively to light, e.g. defoliating beetles, moths of Bihar, hairy caterpillar, tomato fruit borer, tobacco caterpillar, and cerambycid beetles etc. are collected, using light source or by trapping them in a light-trap and are subsequently destroyed.

However, it is a labour intensive and time consuming process. Knowledge of egg laying behaviour, location of eggs and larvae on infested crop is essential Hence, only a well trained person would prove effective.

Cow-dung and clay mixture

The practice of applying a thin paste made of cowdung, clay and cow urine, as a disinfectant, on the floor of mud (kutcha) houses in rural areas is an age old practice. Similarly, the application of a paste, of good consistency, to treat wounds and injured limbs of fruit trees has been in vogue, in villages, since long. Such a paste is also applied to pruned twigs/limbs.

A fine slurry is prepared by thorough mixing of the clay, cowdung and cow urine in a container. The paste is then applied manually using bare hands or a locally made brush.

Cowdung and cow urine possess complex degrading substances and may possess anti bacterial properties. Addition of clay results in better adhesion of other constituents to the treated surface. Sealing of wounds/cut prevents access of pathogens to the otherwise exposed surface. To some extent, the already present pathogen is also dealt by using the applied paste. Pruned ends of twigs and cuts are also favourable spots for the settlement and establishment of woolly (apple) aphid on apple trees. Covering such sites with the cowdung paste hastens healing and prevents aphid settlement. The paste is also used for the treatment of cankered limbs of the trees. The entire effected region is removed by a disinfected knife and is then covered with freshly prepared cowdung paste. As is evident, the application of the paste is a laborious procedure and proper sealing of the injured region is required. Sometimes, it does not prove to be an effective method for the treatment of canker.

Pruning of fruit trees

Pruning and training of fruit trees is an important practice performed during the dormant season to create a proper frame and provide symmetry to the tree and ensure proper and balanced growth in the ensuing season. Set procedures of pruning are followed by using secateurs, knives, pruning saw, etc. Some inconspicuous pests which hibernate as egg nymphs (e.g. some aphids, leaf hoppers, etc.) in limited numbers are automatically removed along with pruned branches/twigs thereby mitigating the severity of their attack in the next season. Further, pruning of old, damaged and weak portion of the tree encourages new growth which is healthier and stronger.

Thus, pruning aids pest control as it realeases overwintering population, improves general health of the tree and helps in maintaining a balanced foliage distribution with proper aeriation and sunlight penetration. Pruned plants usually have lesser pest infestation and do not easily succumb to pest attacks.

However, since pruning is both an art and a skill it demands that the pruner posses basic knowledge of overwintering behaviour and sites of pests to deliver maximum benefit from this mechanical method of pest control.

Use of wood ash on and around vegetable crops

Fruit wood is a major source of energy in the hills, consequently, wood ash is available in plenty. It is used to wash and clean utensils as well as clothes in many areas of Himachal Pradesh. It is a common practice to sprinkle wood ash on vegetable crops, especially growing in kitchen garden and to spread it around plants to ward off pests and to enhance nutrient status of the soil. To achieve this a thick layer of ash is spread on the soil around plants and it is also sprinkled on foliage to protect it against a variety of pests. This is because it is a source of phosphorus for plants and it also acts as a physical poison usually causing abrasion of epicuticular waxes and thus exposing pests to death through desiccation. It also interferes in the chemical signals emanating from the host plants thus obstructing the initial host location by pests. The treated foliage further becomes unpalatable for foliage feeders like cutworms, caterpillars, grasshoppers, etc. But since ash provides only temporary protection against pests, insecticides which have quick knock down effect have replaced the use of wood ash today.

Beating drums and using domestic dogs for combating the menace of birds and monkeys

Birds and monkeys are commonly found vertebrate pests which cause tremendous damage to some ripening crops and fruits. Most bird species are protected by law and monkeys can also not be killed due to religious sentiments. Alternately, the practice of driving them away by beating drums and using well trained dogs has been used since long. Locust-swarms are also warded off by the beating of drums. Today, one or two persons are engaged in these activities during periods of fruiting/crop maturity (along with one or two trained dogs Gaddi or Alsation). While the noise created by the beating of drums and barking of dogs scares birds and monkeys, it requires the employment of regular labourers for constant vigil (Also monkeys and birds may become use to these practices).

Kerosene oil for killing borers

Shoot and stem borers bore and riddle the twigs, branches and even the main trunk of fruit trees and push out faecal matter and frass through an exit hole (Fig. 6.1). Farmers have been using kerosene oil to kill these control tissue borers using a flexible metallic wire which is inserted through the hole made by the borer into the gallery to clean it. Then a small bung made of cloth soaked in kerosene oil is inserted into the hole and finally, it is plugged using a paste of cowdung and clay. The insertion of the metallic wire into the gallery causes physical injury to the larvae which are destroyed in the process. The oil vapour emanating gradually from the cloth bung fill the closed gallery, suffocating the pests and ultimately the larvae die. The death of the borer is indicated by unopened plugged hole. The drawback of this practice is that kerosene vapours act slowly and this treatment is not a sure and definite method to annihilate the borer. Farmers now prefer to use quick acting insecticides for assured results.

Fig. 6.1 Applying kerosine for insect borer

Use of Traditional Devices (Sling and Karban) for Scaring Birds and Stray Animals

In wet temperate Himalayan regions the Sling (Gulel) and the Karban are commonly used for scaring away birds and stray animal for the protection of crops such as maize, fruits and vegetable. For details see Figures 6.2 and 6.3.

Fig. 6.2 Sling and karban (Gulel) for scaring birds and stray animals

Fig. 63 Sling and karban for scaring stray animals

Bajagun Weed for Reducing Rat Menace

Common cowitch, Mucuna prurita, vernacularly known as Bajagun, is a leguminous herbaceous annual plant found throughout the plains of India. It also grows in the low lying areas of Himachal Pradesh. Its longitudinally ribbed turgid pods are covered with dense pale brown or grey stinging bristles (trichomas) which upon coming in contact with the skin cause discomfort and itching attributed to presence of a histanine liberating proteinase, mucunain. The effect persists for 3-5 minutes. These hair also contain serotonin which causes cutaneous pain besides itching. It was an old practice to powder leaves and pods of the plant and scatter it over men-ways and in the live burrows of the rats to drive them away from cultivated fields to reduce rat damage to the crop. After prolonged boiling and throwing away of the water, the pods are also reported to be used as food during famine. The easy availability of various effective rodenticides from the market have resulted in this practice gradually dying out.

Use of walnut and swetflag leaves against pests in stored grains

In rural areas of Himachal Pradesh, it is an old practice to use walnut leaves and leaves of a pond weed, commonly known as sweetflag, Acorus calamus as a protection for both grain and clothes against insect damage. To achieve protection a layer of leaves of walnut is spread over grain stored in gunny bags. Likewise, shade dried leaves of sweetflag are powdered and put over grain stored in gunny bags to protect it from damage due to stored grain pests.

Walnut leaves are astringents and the aqueous extract of fresh leaves possesses bactericidal action while mature leaves contain 9-11 per cent tannin. Tannins are known to act as feeding deterrents. Sweetflag leaves and rhizomes have many chemical ingredients including an essential oil, the oil of calamus, which primarily contains asarone.

Depending upon quantity of asarone (cis as well as trans), its effect on insects may be attractant, antifeedant, repellent, antigonadal or insecticidal. However, since the active principal is present only in meagre amounts (in the leaves) this treatment may not be able to afford protection for long periods.

Indigenous beekeeping practices

Rich indigenous knowledge of beekeeping in a variety of hives such as wall cavities, hollowed logs, skeps etc. served to preserve this heritage. These indigenous hives resemble closely the natural nesting sites of the native honey bee (Apis cerana). Swarms of feral populations of this bee descend to colonize these nests. These are manifestations of rural wisdom and some of them are explained here.

1. The Orchard hives are made of locally available materials viz., stones available on field; clay; chopped wheat straw; sarkanda grass; wood for making frames; string and strips of wood (Fig 6.4).

Fig. 6.4 Orchard hive

First, a platform of stones plastered with mud and measuring 70 cm × 70 cm × 50 cm (l × b × h) is made at a suitable site in the orchard/field. It is given a south-easterly aspect. The brood chamber of standard size for Apis cerana type hive is made on the platform from stones plastered with mud. An entrance hole of about 1.5 cm diameter is provided in one of the lengths, for the easy movement of bees. The top cover is made from sarkanda grass tied with string and supported with strips of wood. It is fashioned as a slopping roof to drain off water.

The low cost and easy to construct structure ensures better temperature regulation inside the hive, enhances its suitability to temperate regions and is helpful in successful overwintering. Appropriate location in the orchard renders it to be very useful for pollination of the target crop and all the scientific management practices can be taken up. Additionally, the structure affords protection from wild animals and is suitable for stationary beekeeping as it cannot be moved even within the orchard

2. Straw hives too, are made using locally available materials. These are: rice straw; locally made string for tying straw; strips of waste wood and wood for making frames (Fig. 6.5).

Fig. 6.5 Straw hive

The rice straw fibres are tied into 5 cm thick sheets with the help of strings and wooden strips. These sheets are cut to size and joined to form a brood chamber 310 mm × 320 mm × 204 mm (l × b × h) in accordance with the standard for Apis cerana frame hive. A hollow razed of bamboo is placed into one of the lengths to provide entrance to bees. A 5 cm thick crown/inner cover is similarly made from rice straw. The top cover is made in the form of a sloping roof from straw or sarkanda grass held in place with sticks. It is left projecting beyond the brood chamber to dram off water. Care has to be taken to ensure that no crevices are left. In addition, no loose straw should project into the brood chamber as it would interfere with bee activity.

This hive is suitable for temperate regions, as its management during peak winter is quite easy and winter-inner or outer packing material is not required. Internal temperature of the hive is also not quickly influenced by changes in environmental temperature. The bees therefore have to spend less energy in temperature regulation within the hive thereby lowering honey consumption and consequently making more honey available for harvesting. Further, overwintering is better as evidenced by larger area under the brood upon the onset of spring.

3. The wall hive is a cavity left in the wall when the house is under construction; it is located at a height of about 150 cm from the floor in kitchens, store rooms, living rooms and/or sheds; the wall hive has an entrance hole of about 2 cm diameter towards the outside; on the inside it is covered usually with a plant of wood plastered with mud. A swarm of Apis cerana descends naturally and settles in this hive making parallel combs. The wall hive is opened only to harvest the honey and never otherwise (Fig. 6.6a & b).

The Apis cerana bee's habit of nesting in natural dark and protected cavities makes the wall hive an ideal home for the swarming bees to descend and colonize. The location of the wall hive at a height in farm houses keeps it away from any disturbance due to activities of the farm's habitants. Human and animal habitation of the farm house, however, provides a relatively constant temperature. Since microclimate of the hive interior is not easily influenced by sudden outside changes, the bees have to spend less energy towards temperature regulation. Further the security offered by human habitation adds to the suitability of the wall hive for bees as they are protected against wild animals such as bears and pine martens.

Fig. 6.6a Wall hive (inside view)

Fig. 6.6b Wall hive

4. The log hive is a simple structure without any frame and separate chamber. Prepared by the hollowing out of a piece of tree trunk, closing both its ends and boring a small hole of suitable size along its length to serve as an entrance. Both horizontal and vertical log hives are in use. Length of horizontal log hives varies from 60-75 cm and the entrance hole which is 6 mm diameter or of pencil thickness is made in the centre. Open ends are closed with a piece of tin or wooden plank or stone mixed with cowdung and clay. 4-5 strips of old combs (3 cm apart) are fixed at each end before use. The vertical log hive is very similar to the horizontal one except that it is placed in an upright position on a piece of tin or flat stone with 5-6 entrances/holes above the base. The top closed end may have 8-10 holes of 1 cm diameter each, if the super box is to be used (Fig. 6.7a & b).

Though movable frames can not be used, as such the scientific management of colonies is not possible and only squeezed honey can be extracted. The advantages afforded by this low cost construction makes it amenable to shifting to orchards for pollination and short distance migration can also be taken up.

Fig. 6.7a Traditional log bee hive

Fig. 6.7b Traditional log hive

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