Pests of Amaranthus and Cucurbits: Identification, Impact, and Management
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The document discusses various pests affecting amaranthus and cucurbits, including their distribution, host range, damage symptoms, and management strategies. Key pests include fruit flies, pumpkin beetles, leaf-eating caterpillars, and stem weevils, each with specific life cycles and control measures outlined. Management recommendations emphasize the importance of cultural practices, insecticides, and the conservation of natural enemies to mitigate pest damage.
Pests of Amaranthus and Cucurbits: Identification, Impact, and Management
- 1. PEST OF AMARANTHUS AND CUCURBITS Submitted to, Dr. Aravind J
- 3. Fruit flies Bactrocera cucurbitae (Tephritidae: Diptera) • Distribution : India, Pakistan, Myanmar, Malaysia, China, Formosa, Japan, East Africa, Australia and the Hawaiian Islands • Host range: Melons, tomato, chillies, guava, citrus, pear, fig, cauliflower, etc. • Damage symptoms Only the maggots cause damage by feeding on near-ripe fruits, riddling them, and polluting the pulp. Damage by the maggots of this pest causes the oozing of brown, resinous fluid from fruits and the fruits become distorted and malformed. The maggots feed on the pulp of fruits and cause premature dropping. The attacked fruits decay because of secondary bacterial infection. After the first shower of the monsoon, the infestation often reaches 100 percent.
- 4. Bionomics The adult flies are reddish brown with lemon-yellow markings on the thorax. Adult flies emerge from pupae in the morning hours and mate at dusk. The female, on average, lays 58-95 eggs in 14-54 days. Egg period 1-9 days larval period 3 – 21 days It pupates deep in the soil The pupae are barrel-shaped, and light brown Pupal period is 6-30 days
- 5. Man age ment 1. Collect infested fruits and dried leaves and dump them in deep pits. 2. Change the sowing date, Use fly traps. 3. Use ribbed gourd as a trap crop and apply carbaryl 1.0 kg or malathion 1.0 L/ha in 500 L water 4. Use attractants like citronella oil, eucalyptus oil, vinegar (acetic acid), dextrose, and lactic acid to trap flies. 5. Conserve pupal parasitoids viz.,Opius fletcheri, O. compensatus and O . Insisus (Braconidae), Spalangia philippinensis and Pachycepoideus debrius. (Pteromalidae), Dirhinus giffardi and D. lzonensis . (Chalcididae). NOTE: In cucurbits, DDT, lindane 1.3 D, copper oxychloride, Bordeaux mixture and sulfur dust should not be used as these are highly phytotoxic.
- 6. Pumpkin Beetles Aulacophora foveicollis, A. cincta, A.intermedia (Galerucidae: Coleoptera) Distribution and status: Widely distributed in Asia, Australia, southern Europe and Africa Host range: Ash gourd ,pumpkin, tinda, ghia tori, cucumber and melon. Damage symptoms • Both grubs and beetles damage. Grubs remain below the soil surface feeding on roots, underground stems of creepers and on fruits lying in contact with the soil The adults feed on those parts of the plant which are above the ground. The early sown cucurbits are so severely damaged that they have to be resown.
- 7. • Management i. Early planting of pumpkin during October – November to avoid damage by this pest ii. Frequent raking of soil beneath the crop to expose and kill the eggs and grubs. iii. Hand collection and destruction of infested leaves and fruits. iv. Spray malathion 50 EC 750 ml, dimethoate 30 EC 500 ml, methyl demeton 25 EC 500 ml, 500 g of carbaryl 50WP in 500-750 L of water per ha or apply 7.0 kg of carbofuran. 3G per ha 3-4 cm deep in the soil near the base of the plants just after germination and irrigate. In their life span of 60-85 days, They lay about 300 oval, yellow eggs singly or in batches of 8-9 in moist soil, near the base of the plants. The eggs hatch in 6-15 days. Grub period 13- 25 days Pupate in thick- walled earthen chambers in the soil, at a depth of about 20-25 cm. The pupal stage lasts 7-17 days The life-cycle is completed in 26-37 days and the pest breeds five times in a year. BINOMICS
- 8. Leaf Eating Caterpillar Plusia peponis, P. signata and P. orichalcea (Noctuidae: Lepidoptera) Distribution : Regular and serious pest all over the country. Damage symptoms The caterpillar cuts the edges of leaf lamina, folds it over the leaf and feeds from within leaf roll. Bionomics Stout adult moth lays spherical sculptured greenish white eggs singly on the tender leaves. Larva is a greenish semi looper with black warts. It is humped on a anal segment. They are active in winter. They pupate in the debris on the ground. Moths are very active at dusk. Management • Collect and destroy caterpillars. • Encourage activity of Apanteles plusia and A. taragamae • Spray malathion 50 EC 750 ml, dimethoate 30 EC 500 ml, methyl demeton 25 EC 500 ml in 500-750 L of water per ha
- 9. Snake gourd semi looper Diaphania indica (Pyraaustidae: Lepidoptera) Distribution: Widely distributed in India. Host range: Melon, gourds, cucumber and cucurbits Damage symptoms Larvae webs leaves and feed. Ovaries and young developing fruits are also eaten. Affected flowers bears no fruits and infested fruits become unfit for consumption. Bionomics • Adult has transparent white wings with broad and dark brown marginal patches and orange coloured anal tuft of hairs in the female. • Eggs are laid singly or in groups on the lower surface of the leaves. Egg, larval, pupal periods last for 3-6, 9-14 and 5-13 days respectively. • Larva elongate bright green with a pair of thin white longitudinal lines on the dorsal side. • Pupation take s place in a cocoon in the flowers. • Adult lives for 3 -7 days and females lays upto 366 eggs.
- 10. Management 1. Collect and early stage caterpillars. 2. Spray Malathion 50 EC or dimethoate 30Ec or methyl demeton 25 EC 500 ml in 500 L of water. 3. DDT, lindane 1.3 D, copper oxychloride, Bordeaux mixture and sulphur dust should not be used as these are highly phytotoxic. 4. Encourage the activity of larval parasitoid of namely Apanteles spp.
- 11. MINOR PESTS
- 12. AMARANTHUS
- 13. Amaranthus stem weevil Hypolixus truncatulus (Curculionidae: Coleoptera) Distribution Specific major pest. Widely distributed in India and neighboring countries. Damage symptoms Grubs bite into stems, feed on pith region making irregular zigzag tunnels and fill with excreta. Stems split longitudinally. Plants dry completely. Adult feeds on tender leaves, makes circular holes in stems, branches and mid-ribs. Attack causes stunting of plants, twisting and swelling of branches and stem and suppression of shoot and leaf production.
- 14. Bionomics Females lay eggs singly in each hole and cover holes with secretion. A female lays 30-34 smooth, oval and pale yellow eggs, egg period 4 to 10 days. A single stem contains 17-20 grubs in it. Grubs are stout, curved, apodous and white in colour. Grub stage lasts for 12 - 24 days. Management 1. Collect and destroy wild amaranthus hosts in the vicinity of cultivated crop. 2. Collect and destroy affected plant parts along with grubs and adults 3. Spray malathion 50 EC 500 ml or endosulfan 35 EC 500 ml or dichlorvos 375 ml in 500 L of water per ha after the harvest of leaves and stems. Plan next harvest 15-20 days later
- 15. Amaranthus caterpillar or Webber Hymenia recurvalis (Pyraustidae: Lepidoptera) Distribution Destructive pest. Widely distributed in tropical and subtropical regions including Africa, Asia and Australia. Host range Amaranthus, beans, melons, spinach, coleus, Luffa spp., grasslands and pastures. Damage symptoms • Larvae scrape the epidermal and palisade tissues of leaves; • Web the leaves with silken threads resulting in drying of webbed leaves.
- 16. Bionomics Adult is a dark brownish black moth with white wavy markings on wings. Spherical snow-white eggs laid singly or in batches of 2 to 5, in grooves of leaf veins. Fecundity is 50 to 80 eggs. Caterpillars are greenish in colour with white lines and black crescents on thorax below lateral line. Fully fed, caterpillars drop down and pupate in soil. Incubation, caterpillar and pupal periods last for 3 to 4, 12 to 16 and 8 to 12 days respectively. Life cycle is completed in 3 to 4 weeks. Collect and destroy affected plant parts along with caterpillars Use light traps @ 1- 2 / ha to attract and kill adults Spray malathion 50 EC 500 ml or endosulfan 35 EC 500 ml or dichlorvos 375 ml in 500 L of water per ha after the harvest of leaves and stems. Plan next harvest 15-20 days later. Management
- 17. Reference • Seni, Atanu. "Insect pests of amaranthus and their management." International Journal of Environment, Agriculture and Biotechnology 3.3 (2018): 1100-1103. • York, A. "Pests of cucurbit crops: marrow, pumpkin, squash, melon and cucumber." Vegetable crop pests (1992): 139-161. • May, Alan Walter Sydney. "Pests of Cucurbit Crops." Queensland Agricultural Journal 62.pt. 3 (1946). • Napier, Tony. "Insect pests of cucurbit vegetables." Prime fact sheet 833 (2009).
- 18. KAAVIYA AV