Insect Pests of Vegetable, Ornamental and Spice Crops (2+1)

Exercise: Insect Pests of Tomato

Exercise - 4

Exercise : Identification of Insect Pests of Solanaceous Vegetables and their Damage Symptoms

Insect Pests of Tomato

1. Tomato fruit borer, Helicoverpa armigera (Noctuidae: lepidoptera):

• Eggs: yellowish white, ribbed, dome shaped and 0.4-0.5 mm in dia.
• Larvae: Newly emerged are yellowish white where as older can be of many colours depending upon the food they consume. Full grown caterpillars are 40-48 mm long with whitish and dark gray longitudinal stripes.
• Adults:
• Medium sized stoutly built moths.
• Forewing is light yellow in males and brown in females.
• On the apical margin of forewings, wavy lines in the form of light black band are visible and a black spot appears on the upper side of the wing.
• On the tip of the abdomen there is a tuft of hairs in case of females, nevertheless, the tuft of hairs is absent in males.

 

2. Serpentine leaf miner, Liriomyza trifolii (Agromyzidae: Diptera)

• Eggs: Newly laid eggs are white and translucent and turn opaque as the development advances. Eggs measure 0.21 to 0.27 mm in length and 0.12 to 0.14 mm in breadth.
• Larvae: The larvae are orange yellow, apodous and move through peristaltic action between the two epidermises of the leaf. There are three larval instars and full-grown maggots are1.88 x 0.70 mm.
• Pupae: The pupae are also orange yellow initially which turn dark-brown on maturity. Length and breadth of pupa is 1.84 and 0.68 mm, respectively.
• Adults: The adults are minute grayish black flies with plum red eyes and a yellow spot on the scutellum. The females are bigger (2.01x0.61 mm) in size than males (1.79x0.52 mm. The females are bigger (2.01x0.61 mm) in size than males(1.79x0.52 mm).

 

3. Greenhouse whitefly, Trialeurodes vaporariorum( Aleyrodidae: Hemiptera)

• Greenhouse whiteflies are small insects with white coloured wings and remain hidden on the under surface of leave. Adults measure about 0.9 to 1.5 mm in length and 0.25 to 0.35 mm in breadth. The eggs are 0.2 to 0.25 mm in length and 0.08 to 0.12 mm in breadth. Newly emerged nymphs are light yellow in colour and measure about 0.25 to 0.30 mm in length and 0.12 to 0.16 mm in breadth. There are four nymphal stages and the last nymphal instar measures 0.70 to 0.90 mm in length and 0.40 to 0.60 mm in breadth. Full grown nymph pupates in a yellow pupal case surrounded by a waxy palisade and waxy fringe.

 

4. Fruit flies, Bactrocera tau (Tephritidae: Diptera)

• Adults: Light brown in colour with lemon yellow curved vertical markings across the thorax. On the apical margin of the forewing, grayish brown patches are present.
• Larvae: Pale or reddish white in colour which tapers anteriorly.
• Pupa: Barrel shaped with dull to reddish yellow in colour. The pupa is barrel shaped with dull to reddish yellow in colour.

5. Hadda beetles (Henosepilachna vigintioctopunctata, H. duodecastigma, H. demurili) (Coccinellidae: Coleoptera)

• The grubs of all the three species are almost 6 mm long, yellow in colour and have six rows of long branched spines. Beetles measure about 8 to 9 mm in length and 5 to 6 mm in breadth. H. vigintioctopunctata beetles are deep copper coloured having 14 black spots on each elytron whose tip is some what pointed. Beetles of H. duodecastigma are deep copper coloured with 6 black spots on each elytron whose tip is more rounded. H. demurili beetles are dull in appearance and light copper coloured with each elytron bearing 6 black spots surrounded by yellow margins.