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1) Enlist any four important insect pests of citrus along with scientific name and describe nature of damage and management of any two insect pests. (Citrus Black Fly, Fruit Sucking Moth)
Lemonbutterfly Papilio demoleus
Citrus-psylla Diaphorina citri
Leaf miner Phyllocnistis citrella
Whitefly Dialeurodes citri
Blackfly Aleurocanthus woghlumi
Fruit sucking moth Budocima fullonica,
Eudocimamaternal,
Achoeajanata
Aphid Toxoptera aurantil
Citrus red scale Aonidiella aurantii
Mealy bugs Ferrisicoccus cameronensis
Leaf miner: Phyllocnistis citrella. S. (Phyllocnistidae: Lepidoptera.)
Economic Importance: Most destructive pests, active in monsoon season, infestation noticed in seedling stage. The pest in suspected to be responsible for the spread of bacterial infection causing ‘citrus canker’
Host Plants: All citrus species.
Life History :
Eggs : singly on underside of leaves I.P. : 3 – 6 days.
Larva : 1 – 2 weeks.
Pupa : Pupation inside the larval mines of leaves P.P. 3 – 4 weeks.
No. of generations : 9 – 13 / year.(Pest is active in monsoon season.)
Population of the pests decreases during hot summer months.
Nature of Damage: On hatching, the larva feed on leaf tissues between upper and lower surfaces
of leaves making glistering zigzag tunnels. The leaves turn pale, curl & finally dry. Besides, mined
leaves may get bacterial infection, which leads to ‘citrus canker’.
Management Practices :
Mechanical control: Use pheromone trap @ 5/acre.
Pruning of affected parts during winter and burning
Removal of infested leaves and their proper disposal in the initial stage.
Chemical control: Carbofuran3%CG @ 20000g/acre
Foliar spray with Imidacloprid 17.8% SL@ 50ml and use spray volume depending on size of tree &Protection equipment used
Foliar spray Permethrin25% EC @160-240 ml in 400 l of water/acre
Granular application with Phorate 10% CG @ 6000 gm/acre
Biological Control:
Natural Enemies: The larvae are parasitised by Cirrospiloideus phyllocnistodes, the euliphod
parasitoid’s Cirripilus quadristriatus and tretrachus phyllocnistoides.
Citrus psylla: Diaphorina citri K. (Psyllidae : Hemiptera)
2) Write scientific name, host plants and management practices of turmeric rhizome fly and Onion thrips.
Turmeric rhizome fly
Scientific name: Mimegralla coeruleifrons
Hostplants: Turmeric and ginger
Management: Destruction of stray plants in offseason, selection of healthy rhizomes for planting. Removal and destruction of rotten rhizomes. Spraying with recommended insecticides.
Onion thrips
- Scientific Name: Thrips tabaci
- Oviposition Site: Female thrips insert eggs into the leaves of onion plants.
- Pupation Site: The larvae drop to the ground to pupate in the soil.
- Damaging Stage: Nymph & Adult
- Nature of Damage: Onion thrips damage onion plants by sucking sap from leaves, causing silvery streaks or blotches, stunted growth, and deformed bulbs.
- Management: Use of Blue Sticky traps, fipronil 5% SC
- Host plants: Polyphagous
3) Explain nature of damage and management practices for mango stone weevil, mango stone borer and hoppers.
- Mango nut weevil
- Damaging Stage: Grub and adult
- Nature of Damage: Grub enter into fruit discolour the pulp OR
Grubs bore through the pulp, enter into the stone and pass entire life inside the stone.
- Management: Spray the kerosene oil, Digging of Soil, Destruction of infected fruit OR
Ploughing of orchard after harvest. Collection and destruction of infested and fallen fruits. Destroy all left over seeds in the orchard and also in the processing industries
The mango stone borer (Hypochrysopsarafa) is an insect pest that primarily affects mango trees. The adults of this pest are small beetles that lay their eggs on the fruit or near the base of the fruit stalk. The larvae then bore into the fruit, feeding on the flesh and causing damage.
- Mango stone borer
Nature of damage:
1. Fruit damage: The larvae bore into the mango fruit, creating tunnels and feeding on the pulp. This feeding activity can lead to rotting, discoloration, and spoilage of the affected fruit. The damaged fruit becomes unfit for consumption and loses its market value.
Management practices:
1. Cultural practices: Proper cultural practices are essential to manage mango stone borers. Some measures include:
- Sanitation: Regularly remove fallen fruits and destroy them to minimize the population of the pest.
- Pruning: Prune and remove infected branches and twigs to prevent the spread of the pest to healthy parts of the tree.
- Irrigation and fertilization: Ensure that the mango tree is receiving optimal irrigation and nutrient levels to maintain its health and vigor, making it less susceptible to pests.
2. Biological control: Implement biological control methods to manage mango stone borers. These include:
- Natural enemies: Encourage the presence of natural enemies such as parasitic wasps, predatory beetles, and ants that feed on mango stone borers.
- Biological control agents: Release beneficial organisms like Trichogramma wasps, which parasitize the eggs of the pest, or entomopathogenic nematodes, which infect and kill the larvae.
3. Chemical control: If the infestation levels are severe, chemical control may be warranted. However, it is important to follow proper pesticide application practices and adhere to local regulations. Some considerations include:
- Insecticide selection: Choose an insecticide that is specifically labeled for mango stone borers and follow the recommended dosage.
- Timing: Apply insecticides at the appropriate time, considering the life cycle of the pest, to target the most vulnerable stage.
- Rotational use: Rotate different classes of insecticides to prevent the development of resistance in the pest population.
4. Trap crops: Planting trap crops, such as guava or other suitable host plants, nearby can attract the mango stone borers. Regularly monitor and destroy the infested fruits on the trap crop, reducing the pest population in the main mango orchard.
5. Monitoring: Regularly monitor mango trees and fruits for signs of infestation. This allows for early detection and timely intervention, preventing the spread of the pest and minimizing damage.
Integrated pest management (IPM) practices that combine various strategies, such as cultural practices, biological control, and targeted chemical control, should be employed for effective and sustainable management of mango stone borers.
- Mango hoppers
Nature of damage: The nymphs and adults suck the sap from the tender leaves, inflorescence causing withering and shedding of flowers. The hoppers also secrete honeydew which encourages the development of fungi.
Management practices: Avoid dense planting. Keep orchards clean by regular ploughing and removal of weeds. Avoid excess use of nitrogenous fertilizers. Smoking of orchards by burning of crop residues/cow dung cake during evening hours. Application of bio-agents, Metarhizium anisopliae or Beauveria bassiana. Spraying of recommended insecticides.
4) Describe shoot and fruit borers on okra and brinjal.
- Okra Shoot and Fruit Borer
Scientific name: Earias vitella, E. insulana (Noctuidae: Lepidoptera)
Site of oviposition: On shoot tips, buds, flowers and fruits
Nature of damage: Caterpillar bores into tender terminal shoots in the vegetative stage and buds, flowers and flower young fruits in the fruit stage. The shoots dry droop, wither and up. The fruits are deformed and become unfit for holes are consumption. Bored plugged with excreta.
Management practices: Resistant cultivars like AE 57, PMS 8, Karnual Special, Collect and destroy infested shoots, buds, flowers and fruits. Remove the alternate hosts, Egg parasitoid T. chilonisand larval parasitoid Chelonusblackburnii. First instar larvae of Chrysoperlacarnea@ 1 lakh/ha. Set up light traps, pheromone traps @5/ha. Spray Bit formulation @ 2 g/lit. Spray NSKE 5% or Azadirachtin 5% 400 ml or Fenpropathrin 30 EC 250-340 ml with 500 L water/ha.
- Brinjal Shoot and Fruit Borer
6) Enlist any four important insect pests of cruciferous vegetables along with scientific name and describe nature of damage and management of any two insect pests.
- Oviposition Site: Cavities of the trunk
- Pupation Site: inside affected trunk
- Damaging Stage: Grub and Adult
- Nature of Damage: Grub make zig-zag burrow in bark, tunnel in the bark
- Management: probe method, extract grub with hooked iron method
Banana Rootstock
- Scientific Name: Cosmopolites sordidus
- Oviposition Site: Grub and adult
- Pupation Site: The larvae pupate in the soil.
- Damaging Stage: The larvae feed on the roots, causing damage to the root system.
- Nature of Damage: Bore into stem a feed inside
- Management: Cultural practices such as proper sanitation, avoiding planting in infested areas, and Removal of Pseudostem
e) Mango fruit fly
Fruit fly
- Scientific Name: Dacus dorsalis
- Oviposition Site: fruit
- Pupation Site: soil
- Damaging Stage: maggots
- Nature of Damage: maggots feed on pulp
- Management: Trapping using fruit fly traps, bait sprays, fruit bagging, male annihilation techniques, insecticide application
f) Red palm weevil
- Oviposition Site: base of leaf sheath.
- Pupation Site: cocoons
- Damaging Stage: Grub
- Nature of Damage: Grubs bore into trunk, feed on soft tissue
- Management: monocrotophos @ 20 ml/palm.
g) Potato tuber moth
The potato tuber moth, also known as the potato tuber borer, is a pest that primarily affects potato plants. The adult moth lays its eggs on potato plants, and the larvae then tunnel into the tubers, causing damage and making them unsuitable for consumption or storage.
The larvae of the potato tuber moth feed on the flesh of the potato tubers, creating tunnels and galleries. This feeding activity not only damages the tubers but also provides entry points for other pathogens, leading to rot and decay. Infested potatoes may have holes, tunnels, and frass (insect excrement) present.
To manage potato tuber moths, several strategies can be employed. One option is the use of insecticides, both chemical and organic, which can be applied to the foliage and tubers of the potato plants. It is important to follow label instructions and consider the potential impact on beneficial insects and the environment.
10) Define Nematode. Explain characteristics of Plant parasitic Nematodes. Give important symptoms caused by nematodes.
A nematode is a type of roundworm that belongs to the phylum Nematoda. These worm-like organisms are elongated, unsegmented, and typically microscopic in size. Nematodes can be found in various terrestrial and aquatic habitats, including soil, freshwater, and marine environments. While many nematodes are free-living and play important roles in nutrient cycling, some species are parasitic and can cause damage to plants, animals, and humans.
Plant-parasitic nematodes are those that specifically infect and feed on plant roots or other plant tissues. They have a specialized feeding structure called a stylet, which they use to pierce plant cells and extract nutrients from the host plant. Plant parasitic nematodes reproduce rapidly and can cause significant damage to crops and ornamental plants.
Characteristics of plant-parasitic nematodes include:
1. Host specificity: Different species of nematodes have specific host ranges, meaning they can only infect and reproduce on certain plant species or within specific plant families.
2. Sedentary or migratory behavior: Some nematodes, known as sedentary nematodes, remain in one feeding site on the plant root for their entire life cycle. Others, called migratory nematodes, move through the soil and feed on multiple plant roots.
3. Damage mechanism: Nematodes can cause damage to plants through direct feeding, which leads to the destruction of plant cells and tissues. They can also transmit viruses and other pathogens to the plant, further exacerbating the damage.
Important symptoms caused by nematodes in plants include:
1. Stunted growth: Nematode feeding on plant roots can lead to reduced absorption of water and nutrients, leading to stunted growth and poor plant vigor.
2. Root galling: Many nematode species induce the formation of swollen or distorted root structures called galls. These galls impede the flow of water and nutrients in the plant and can further weaken the root system.
3. Wilting and yellowing: Nematode-infested plants may exhibit wilting, even when soil moisture is adequate. The nematodes interfere with the plant's ability to take up water and nutrients, causing wilting and yellowing of leaves.
4. Reduced yield: Severe nematode infestations can lead to reduced crop yield and quality. The damage caused by nematodes can result in poor plant health, reduced flowering or fruiting, and decreased productivity.
5. Other symptoms: Depending on the specific nematode species and plant host, other symptoms may include root necrosis, root rot, leaf chlorosis, and general decline in plant health.
It is essential to accurately diagnose and manage nematode infestations to prevent further damage to plants and minimize yield losses in agricultural systems. Proper crop rotation, sanitation practices, nematode-resistant cultivars, and the use of nematicides may be employed as part of an integrated pest management approach to control plant-parasitic nematodes.
11) Write short notes:
a) Chilli mites
Scientific name: Polyphaogotarsonemus latus
Nature of damage : Both nymphs and adults suck the sap from young foliage and growing tips.
Management: Resistant or tolerant varieties Pusa jawla, Phule jyoti. Chilli crop bordered by two rows of maize at every 0.5 acre area (31.2 x 60 sqm). Management of nutrients and water will also helps in reducing the mite population. Conserve the predators. If the incidence ofmites is low, spray neem seed powder extract 4% at 10 days interval Soil application of Phorate 10 G@10 Kg/ha. Spray recommended acaricides.
b) Snails and slug
Snails and slugs belong to invertebrate phylum Mollusca (class- Gastropoda). These are amphibious capable of living on land and waters. Snails differ from slugs in having a spirally coiled shell over their body. The snails live in humid condition. They are nocturnal and damages to vegetables, ornamental and plantation plants etc.
Common species of snails: Common garden snail- Helix sp. Green house snail - Opeas gracilis. Giant African snail- Achatinafulica
Slug- Limax Sp.
Control measures : Hand picking. Use of Metaldyde.
c) Cultural control of plant parasitic nematodes
Cultural nematode control methods are agronomical practices employed in order to minimize nematode problem in the crops.
- Selection of healthy seed material
- Adjusting the time of planting
-Fallowing
- Deep summer ploughing
-Crop rotation
-Manuring
-Flooding
-Trap cropping
-Antagonistic crops Removal and destruction of infected plants
-Use of resistant varieties
d) Rhinoceros Beetle
- Scientific Name: Oryctes rhinoceros
- Host plants: Coconut and other palms.
- Oviposition Site: Adult beetles lay eggs in decaying organic matter, such as compost piles or dead trees.
- Pupation Site: Larvae pupate in the soil or in decaying matter.
- Damaging Stage: Grub and adult
- Nature of Damage: Damage tender plant parts
- Management: Removing decaying organic matter, Aggregation Pheromone- rhinolure, probe method
h) Diamond black moth
- Scientific Name: Plutella xylostella
- Oviposition Site: Female moths lay eggs on the undersides of leaves.
- Pupation Site: leaves.
- Damaging Stage: The larvae (caterpillars) are the damaging stage as they feed on leaves.
- Nature of Damage: feed on epidermis of leaves
- Management: Integrated pest management (IPM) practices, malathion and Hand Picking
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