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Insect and non-insect pests cause extensive damage to standing crops, stored grains and stored products resulting in huge economic loss. Besides these, several pests cause annoyance, as well as attack livestock such as, cattle, poultry and pet animals. Some others damage household articles such as, clothing, upholstery, carpets, paper, books, leather articles, wooden and bamboo furniture and all sorts of wooden structures. These obnoxious creatures besides consuming any kind of food materials, spoil them by contaminating and polluting them with their faecal matter and urine and impart a repulsive, bad odor and make them unfit for consumption by humans and livestock. The damages caused by them pave the way for easy access and infection by some of the saprophytic microorganisms, which hasten the deterioration process. A few of these microorganisms produce mycotoxins, which are poisonous and may even be fatal to the consumers.

Among the household pests, cockroaches, crickets, silver fish, ants, white ants, carpet and powder post beetles and clothes moths are quite important. These insects not only cause annoyance but different types of flies, mosquitoes, bugs, fleas and lice either suck and feed on the blood from humans, cattle, poultry etc. but are also responsible for disseminating several disease causing microorganisms.

Mango (Mangifera indica)

1. Mango hoppers

(i) Amritodes atkinsoni (ii) Idioscopus niveosparsus and (iii) I. clypealis

Order - Hemiptera

Suborder - Homoptera

Family - Cicadellidae

Nature of damage. Three different species of hoppers are found to cause damage to mango trees. During some years, especially during the months of November-February, when the mango trees come to flowering, the pest appears in large numbers. During the other months, the pests are seen in much lesser numbers in an active form, while the other insects hibernate under the bark of the trees. Even in the peak period of pest occurrence, after a few heavy showers, the number of insects is considerably reduced.

During the cold season, when the trees put out the flower spikes, thousands of hoppers, young and adults appear in large numbers, pierce, suck and feed on the sap from the tender shoots, flower stalks, flowers and buds. This drain of the sap causes the buds and flowers to dry, wither and they are shed in large numbers, as a result fruit production may go down by 25-60 per cent. When a severely infested tree is approached, thousands of hoppers hop or fly about and make a rustling noise, as they dash against the foliage. The hoppers exude a sweet, sticky fluid excretion and this fluid thrown out by myriads of these insects after feeding on the tree sap, wets the soil underneath the trees and on the surface of the leaves of the trees. In case of severe infestation, the fluid may fall down in drops. The secretion attracts scores of flies, bees and other insects, which come to feed on the secretion. The infested tree presents a sickly appearance. The trees get devoid of buds and blossoms. The leaves appear shiny and are covered by ‘sooty mould’, a fungal disease. Thousands of caste skins of the nymphs are found on the shoots and leaves. The continuous damage caused to the trees year after year by the pest makes them loose their vigor gradually and eventually leads to severe reduction in their yielding capacity.

Life cycle of the pest. The female hopper inserts spherical, pale whitish eggs singly into the plant tissues through slits made in the young shoots, flower stalks and flower spikes. The eggs hatch in 4-6 days and the young nymph hatching out of the egg looks quite similar to the adult. The nymphs are very active and move about rapidly along the flower spikes and shoots, suck and feed on the plant sap. They are smaller in size, wingless and unable to fly or jump. The young ones moult their skin a few times during their growth and become adults in 10-15 days. The adult hoppers are small insects, about 3.0 mm. in length with a wedge-shaped body. The head is broader and the body gradually narrowing backwards. The legs are well developed, especially the hind legs. The general color is light greenish-brown. They are extremely active and can fly and hop around. They have a tubular, sucking mouthpart by which they puncture the tender plant parts and floral parts. The adults of Idioscopus clypealis are smaller, with two black spots on the prothorax and a few black spots on the front portion of the head, while those of Idioscopus niveoparsus are slightly bigger with three black spots on the prothorax and whitish, distinct cross bands on the light brownish forewings. The adults of Amritodes atkinsoni are bigger than the other two species, about 5.0 mm. in length, with two black spots on the prothorax. Two or more generations may appear during the flowering season of mango trees (Fig.71).

PESTS OF CEREALS

Rice (Oryza sativa)

Rice is the staple food of a vast majority of people throughout the world, especially in India. Rice crop is grown in about 75 million acres, which is about one-third of the total world area under rice. The warm and humid environment for the rice crop is best suited for invasion by several insect pests and as many as 85 species of insects are known to infest this crop. The damages caused by different pests extend from the seedling to harvest stages of the crop. Some of these pests are widely distributed and cause extensive damage. The more important pests are described below:

1. Rice stem borer or Rice yellow stem borer

Scirpophaga (Tryporyza) incertulas

Order - Lepidoptera

Family - Pyraustidae

Among the pests, which ravage rice crop, ‘rice stem borer’ is a major one and infests rice crop at all growth stages, from seedling to flowering. It is a specific pest of rice alone and is more serious during the months of October-January. The pest has a wide distribution in all Asian countries. The damages caused by this pest ranges from 5-20 per cent. Generally, late varieties of rice are more severely infested than the early maturing varieties, because of the possibility of the pest multiplying in larger numbers by the time the late varieties come to maturity. Cold weather with high humidity and low temperature prevalent during October-December is found to be conducive for the multiplication of the insect.

Failure in timely diagnosis of diseases and other pests has often been responsible for devastating losses. Reducing crop losses by keeping pests at bay is crucial to food security. Plant clinic is an innovative paradigm which plays a vital role in assuring food security and ushering prosperity by providing timely diagnosis and rendering necessary advice to the growers, gardeners and other stakeholders for managing pest problem in India. Plant clinics are all about plant health. Though the major role of plant clinic lies in diagnostics and advisory, the activities of plant clinic extend beyond plant clinic, with emphasis on extension, working more closely with farmers and organizations involved in promoting food production. The role of plant clinics beyond diagnostics and advisory. These are:

Gaseous poisons use to kill insects are called as fumigants. Fumigants are pesticides that form poisonous gases when applied. Some active ingredients are liquids when packaged under high pressure but change to gases when they are released. Other active ingredients are volatile liquids when enclosed in an ordinary container and so are not formulated under pressure. Still others are solids that release gases when applied under conditions of high humidity or in the presence of water vapor.

Definition

Seed treatment is the process by which seeds are treated with physical, chemical or biological agents to prevent the infection of seedlings and the subsequent development of the crops.

Advantages of Seed Treatments

Increased seed germination.

Ensures uniform seedling emergence.

Protect seeds or seedling from early season diseases and insect pests improving crop emergence and its growth.

Lower seedling mortality.

Improved plant population and thus higher productivity.

Reduces the cost and the potential environmental impact.

Also reduces the probability of chemical residues in harvested grain.

Relatively easy and cheap to apply compared to broadcast sprays.

Proper selection of a fungicide and its application at the correct dose and the proper time are highly essential for the management of plant diseases. The basic requirement of an application method is that it delivers the fungicide to the site where the active compound will prevent the fungus damaging the plant. The fungicidal application varies according to the nature of the host part diseased and nature of survival and spread of the pathogen. The method which are commonly adopted in the application of the fungicides are discussed.

1.Soil treatment

2.Seed treatment

3.Foliar or vegetative application

Insect Control and Insecticides

Control Tips

Practicing Integrated Pest Management can significantly reduce the amount of insecticides needed to control many insect problems.

Broad-spectrum insecticides are effective against all insects, even the good ones. Other insecticides target certain insects. Using a targeted insecticide minimizes the risk to beneficial or non-target insects.

Some insecticides work immediately to kill insects while others may need some time to take effect.

Using more than one insecticide product in the same location can increase or decrease each one’s effectiveness. It may also result in a greater risk to health and/or the environment.

Insect growth regulators like pyriproxyfen and methoprene do not kill insects; they make it impossible for exposed insects to molt (grow) or lay eggs properly.

Insecticidal baits can be used instead of spraying large areas, especially for social insects like ants. This can decrease the risk of exposure, but remember to place baits where children and pets won’t have access.

A. Purchase

a)Do not purchase leaking containers, loose, unsealed or torn bags.

b)Do not purchase pesticides without proper/approved labels.

c)Purchase only just required quantity e.g. 100, 250, 500 or 1000 g/ml for single application in specified area.

Effective application of pesticides depends on many factors. One of the more important is to correctly calculate the amount of material needed. Unless you have the correct amount of pesticide in your tank mix, even a correctly calibrated sprayer can apply the wrong rate.

Manufacturers provide application rate instructions on every pesticide label. Due to the variety of ways in which these recommendations are stated (such as lbs. of active ingredient (a.i.) per acre, lbs. of formulation per 100 gal. of spray, or ozs, of a.i. per 1,000 sq. ft.) it is often necessary to adapt the recommendations to different areas and volumes, or even other units. Sometimes the amount of active ingredient must be converted to the amount of actual product. This process can be very confusing.

Solid formulations such as dust, wettable powder or granules, the active ingredient is mixed with inert material. The concentration is expressed as:

Active ingredient (%) in the total weight of commercial product.

Calibration is the process of measuring and adjusting the amount of pesticide your equipment applies or delivers to a specific area. The purpose of calibration is to ensure your equipment is applying the correct amount of material uniformly over a given area.

Equipment is manufactured to be adjustable. Charts or tables may be provided to assist the operator in making adjustments to the settings. These recommended settings, however, are only approximate and may not be appropriate for all situations. Therefore, your equipment must be calibrated periodically. This depends on the type of equipment and the frequency of use. The application rate of the sprayer is affected by travel speed, nozzle size, and sprayer pressure. Equipment is calibrated by making a trial run on some premeasured area and measuring the output. For example, using a hand-held sprayer, spray a premeasured test area with water using the same pressure and techniques (i.e., travel speed and equipment) you would use when applying the pesticide. After spraying the test area, determine how much water was used. This volume can then be used to calculate the amount of water and pesticide needed to cover the intended application area.

The time invested in calibrating your equipment is time well spent. Accurate calibration to determine the application rate under your operating conditions is important for cost, efficiency and safety.

The objective of correct pesticide application cannot be achieved without good quality Plant Protection Equipment. A sound designed machine shall be proficient as far as pesticide distribution and delivery to the target in minimum time with least wastages is concerned. Hence, the machines should be tested to ascertain that they are:

i) Common Maintenance

Clean outer surface with brush or cotton waste by using plenty of water or kerosene oil.

Oil the moving or rubbing surfaces of parts with lubricating oil or grease.

Filter the chemical solution/ fuel oil mixture while pouring into the tanks. Make the caps or lids leak-proof with gaskets.

Flush the equipment with clean water to wash inside parts of containers, tubes and nozzles to be free from chemicals.

Any sprayer nozzle essentially breaks the liquid into small droplets and throws them. All nozzles in the field produce rangesof droplets of different size called spray spectrum. The hydraulic nozzles have wide range of size of droplets whereas the rotary nozzles have narrow range. Adroplet of 400 µm diameter is 1000 times bigger in volume than a droplet of 40 µm. The volume of spherical droplets can be worked out as 4/3 µr3. So if the droplet size of aspraying system could be reduced to half, then there will be 8 fold increases in the number of droplets and the coverage will also increase.

Majority of the pesticides are applied as sprays. The liquid formulations of pesticide either diluted or directly are applied in small drops to the crop by different types of sprayers. Generally the wettable powder, EC formulations are diluted suitably with water which is a common carrier of pesticides. However, in few cases oil is used as carrier of pesticides.

Spraying nozzle is a device for emitting spray liquid, breaking it up into small droplets and throwing the droplets away from the nozzle orifice. Different designs of nozzle are used to produce appropriate droplet size spectrum. In order to break the liquid into droplets energy is needed. The spray nozzles therefore are classified as:

Pesticide Dusting

The dusting powders are low concentration ready to use type, dry formulations containing 2 to 10% pesticide. The inert material or dry diluents is talc, soapstone, attapulgite, etc. and it is non toxic. The sulphur dust is not diluted with inert material.

Sprayer is an equipment in which the spray fluid is broken up into fine droplets and ejected under pressure. Actually, the function of the sprayer is to provide the spray fluid with some energy so that it can be broken into fine droplets through the nozzle and propelled to the target. The energy can be produced manually or with the help of any other source of power. There are a variety of sprayers.

Type of Sprayers: There are a variety of sprayers.

The Effectiveness of a Pesticide in Controlling a Disease and Pest Depends on

Using the right pesticide for the target disease & pest.

Applying the pesticide at the right time.

Applying the pesticide in the right amount.

Applying the pesticide to the right place.