Spinach: Insect and Mite Pests

Leaf eating caterpillar/gram pod borer

• Egg: The spherical, yellowish eggs are laid singly on tender parts and buds of plants. The egg period lasts for 2-4 days.
• Larva: Caterpillars are of varying colour, initially brown and later turn greenish with darker broken lines along the side of the body. Body covered with radiating hairs. When full grown, they measure 3.7 to 5 cm in length. The full grown caterpillar pupates in the soil in an earthen cell. The larval period lasts for 18-25 days.
• Pupa: Pupation takes place inside the soil; pupal stage lasts 7-15 days.
• Adult: Moth is stout, medium sized with brownish/greyish forewings with a dark cross band near outer margin and dark spots near costal margins, with a wing expanse of 3.7cm.

• Young larva feeds on the leaves. Internal tissues are eaten severely and completely hollowed out.
• While feeding, the caterpillar thrust its head inside leaving the rest of the body outside. Fed leaves, shoots and buds.

• Parasitoids : Trichogramma chilonis, Tetrastichus spp., and Telenomus spp., Braconid wasp, Ichneumon spp., Bracon hebetor, Goniophthalmus halli, Carcelia spp., Campoletis chlorideae; Lissopimpla excels, Ichneumon promissorius
• Predators: Lacewings, king crow, dragonfly, spider, robber fly, reduviid bug, praying mantis, red ant etc.,
• Entomopathogenic nematode: Ovomermis albicans

Tobacco caterpillar

It is found throughout the tropical and sub-tropical parts of the world, wide spread in India. Besides tobacco, it feeds on cotton, castor, groundnut, tomato, cabbage and various other cruciferous crops.

• Egg: Female lays about 300 eggs in clusters. The eggs are covered over by brown hairs and they hatch in about 3-5 days.
• Larva: Caterpillar measures 35-40 mm in length, when full grown. It is velvety, black with yellowish – green dorsal stripes and lateral white bands with incomplete ring – like dark band on anterior and posterior end of the body. It passes through 6 instars. Larval stage lasts 15-30 days
• Pupa: Pupation takes place inside the soil, pupal stage lasts 7-15 days.
• Adult: Moth is medium sized and stout bodied with forewings pale grey to dark brown in colour having wavy white crisscross markings. Hind wings are whitish with brown patches along the margin of wing. Pest breeds throughout the year. Moths are active at night. Adults live for 7-10 days. Total life cycle takes 32-60 days. There are eight generations in a year.

• In early stages, the caterpillars are gregarious and scrape the chlorophyll content of leaf lamina giving it a papery white appearance. Later they become voracious feeders making irregular holes on the leaves.
• Irregular holes on leaves initially and later skeletonization leaving only veins and petioles
• Heavy defoliation.

• Maximum S. litura built up at temperature ranges from 26.0°C to 35.1°C, relative humidity ranges from 89 and 62 per cent, zero rainfall, total sunshine hours (64.6 hrs/week), S. litura population shows a positive correlation with relative humidity, sunshine hours, whereas negatively correlated with wind velocity . Parasitoids and predators same as in Helicoverpa armigera

Beet armyworm

• Egg: Eggs are laid in clusters of 50 to 150 eggs per mass. Normal egg production is about 300 to 600 per female. Eggs are usually deposited on the lower surface of the leaf, and often near blossoms and the tip of the branch. The eggs are greenish to white in color, and covered with a layer of whitish scales that gives the egg mass a fuzzy or cottony appearance. Eggs hatch in 2-3 days during warm weather.
• Larva: There normally are five instars, although additional instars are sometimes reported. Duration of the instars under warm (summer) conditions is reported to be 2.3, 2.2, 1.8, 1.0, and 3.1 days, respectively. The larvae are pale green or yellow in color during the first and second in stars, but acquire pale stripes during the third instar. Larvae during the fifth instar are quite variable in appearance, tending to be green dorsally with pink or yellow color ventrally and a white stripe laterally. A series of dark spots or dashes is often present dorsally and dorsolaterally. The body is practically devoid of hairs and spines.
• Pupa: Pupation occurs in the soil. The chamber is constructed from sand and soil particles held together with an oral secretion that hardens when it dries. The pupa is light brown in color and measures about 15 to 20 mm in length. Duration of the pupal period 6-7 days during warm weather.
• Adult: The moths are moderately sized, the wing span measuring 25 to 30 mm. The forewings are mottled gray and brown, and normally with an irregular banding pattern and a light colored bean-shaped spot. The hind wings are a more uniform gray or white color, and trimmed with a dark line at the margin. Moths usually live for 9-10 days.

• Larvae feed on foliage. Young larvae feed gregariously and skeletonize foliage.
• As they mature, larvae become solitary and eat large irregular holes in foliage.
• They also burrow into the crown or center of the head on lettuce, or on the buds of cole crops.

• Parasitoids: Telenomus remus, Trichogramma spp.
• Predators: Pentatomid bugs, earwigs, red ants, spiders, reduviid bug, wasps, Bracon spp., Chelonus spp. etc.

Cutworm

• Egg: The egg is white in color initially, but turns brown with age. It measures 0.43 to 0.50 mm height and 0.51 to 0.58 mm wide and is nearly spherical in shape, with a slightly flattened base. The eggs normally are deposited in clusters on foliage. Females may deposit 1200 to 1900 eggs. The egg period is 3-6 days.
• Larva: There are five to nine instars, with a total of six to seven instars most common.
• Pupa: Pupation occurs belowground at a depth of 3 to 12 cm. The pupa is 17 to 22 mm long and 5 to 6 mm wide and dark brown. Duration of the pupal stage is normally 12 to 20 days.
• Adult: The adult is fairly large in size, with a wingspan of 40 to 55 mm. The forewing, especially the proximal two-thirds, is uniformly dark brown. The distal area is marked with a lighter irregular band, and a small but distinct black dash extends distally from the bean-shaped wing spot. The hind wings are whitish to gray, and the veins marked with darker scales. Moths select low-growing broadleaf plants preferentially for oviposition, but lacking these will deposit eggs on dead plant material. Soil is an unsuitable oviposition site.

• Larvae can consume over 400 sq cm of foliage during their development, but over 80% occurs during the terminal instar, and about 10% in the instar immediately preceding the last.
• Thus, little foliage loss occurs during the early stages of development.
• Once the fourth instar is attained, larvae can do considerable damage by severing young plants, and a larva may cut several plants in a single night. Plants tend to outgrow their susceptibility to injury.

• Parasitoids: Apanteles merginiventris, Chelonus insularis, Hyposoter exigua, Lespesia archippivora.
• Predators : Spider, ground beetle, lacewing, reduviid bug, pentatomid bug, predatory bug, praying mantis, wasps, ants etc.
• Entomopathogenic nematode: Hexameris arvalis.

Amaranthus weevil

• Egg: The eggs are yellowish in colour and normally are deposited in clusters on foliage. Duration of the egg stage is 3-6 days.
• Grub: Body brownish-green with sparse white hairs; thin black dorsal line, broad dark sub dorsal stripes, and paler yellowish sides and bottom.
• Pupa: The pupa is 17 to 22 mm long and 5 to 6 mm wide, and dark brown.
• Adult: Wingspan 19-21 mm, forewing dark brown or gray with broad white median band beginning at inner margin and terminating in “fish-hook” shape before reaching costa. Hindwing dark brown with broad white median band across wing; band is fairly straight with smooth margins outlined in black.

• Larvae feed on beets, chard, spinach, and various other crops.

• Predators: Spider, ground beetle, lacewing, reduviid bug, pentatomid bug, predatory bug, praying mantis, wasps, ants etc.

Aphid

• Egg: Eggs are very tiny, shiny-black, and are found in the crevices of bud, stems, and barks of the plant. Aphids usually do not lay eggs in warm parts of the world.
• Nymph: Nymphs (immature stages) are young aphids, they look like the wingless adults but are smaller. They become adults within 7 to 10 days.
• Adult: Adults are small, 1 to 4 mm long, soft-bodied insects with two long antennae that resemble horns. Most aphids have two short cornicles (horns) towards the rear of the body.

• Infesting tender shoots and under surface of the leaves.
• Curling and crinkling of leaves
• Stunted growth
• Development of black sooty mould due to the excretion of honeydew

• Parasitoids: Aphidius colemani, Aphelinus spp. And Diaeretiella sp
• Predators: Red ant, robber fly, big-eyed bug ( Geocoris sp), earwig, ground beetle, cecidomyiid fly, lacewing, ladybird beetle, spider, praying mantis, reduviid bug, dragonfly, hoverfly etc.

Leaf miner

• Egg: Minute orange yellow, apodous maggot feeds on chlorophyll mining in between epidermal layers. Egg period is 4 days.
• Larva: Full grown maggot measures 3 mm. Larval duration is about 7 days.
• Pupa: Pupation takes place inside a thin loose mesh of silken cocoon. Pupal period is about 7 days.
• Adult: It is a pale yellowish fly, measuring 1.5 mm in length. The female fly punctures upper surface of leaf to lay eggs singly. Total life cycle takes 3 weeks.

• Leaves with serpentine mines. The maggot punctures the epidermal layers and scraps the chlorophyll content between the layers.
• In severe cases the photosynthetic activity reduced and leads to death of the plant.
• Drying dropping of leaves in severe cases.

• Warm weather conditions are favourable for multiplication.

• Parasitoids: Gronotoma micromorpha (larva and pupa), Diglyphus sp (larva), Halticoptera circulus and Opius sp (pupal) Chrysocharis sp, Neochrysocharis formosa.
• Predators: Robber fly, spider, red ants etc.

Spinach crown mite

• Crown mite eggs are transparent and spherical and are laid in the innermost parts of the plant. Immature are similar to adults except smaller in size known as protonymph. Adults are tiny, almost transparent mites with prominent long hairs. They can be found in both the soil and in the crowns of susceptible plants. They live deep in the crown of the spinach plant and lay eggs on the new growth.

• Crown mites may damage sprouting seeds, seedlings before or after emergence, or older plants.
• They feed primarily on newly expanding leaves at the heart of the plant.
• Their ability to injure the crop decreases as plants get larger and as plants grow rapidly.
• The damage appears as deformed leaves or as small holes in expanding leaves.
• Vector for plant pathogens – Pythium sp and Rhizoctonia sp

• Predators: Predatory mite, predatory thrips, Oligota sp., Orius sp. (pirate bug), mirid bug etc.

IPM for Spinach

To know the IPM practices for Spinach, click here.

Source: NIPHM,  and Directorate of Plant Protection, Quarantine & Storage