BIOLOGY AND MANAGEMENT OF TOMATO PINWORM, Tuta absoluta (Meyrick) WITH BIOCONTROL AGENTS
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Date
2018
Authors
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Publisher
Acharya N.G. Ranga Agricultural University
Abstract
Studies on biology including morphometrics of Tuta absoluta
(Meyrick) (Lepidoptera : Gelechiidae), biology and its predatory potential of
Nesidiocoris tenuis (Reuter) (Hemiptera : Miridae) on T. absoluta, and
evaluation of different trichogrammatids against T. absoluta were conducted
at Insectary, Department of Entomology, S.V. Agricultural College,
Tirupati, Andhra Pradesh during 2017-18.
The biology of T. absoluta on tomato, potato and brinjal was studied.
Adult longevity in days of T. absoluta on tomato was higher (9.63),
compared to potato (8.74) and brinjal (7.55). The mean egg period, duration
of I, II, III and IV larval instars, pupa and total life period on tomato, potato
and brinjal were 4.57, 4.91, 6.12; 2.31, 2.92, 3.02; 2.29, 2.90, 3.45; 3.28,
4.07, 4.64 and 3.26, 4.26, 5.59; 7.43, 9.53, 9.81 and 32.79, 37.35, 39.20
days, respectively. The mean fecundity of T. absoluta was 151.31, 57.26 and
34.5 eggs/female, respectively and sex ratio was 59.26 and 40.73; 55.95 and
44.04 and 62.16 and 37.83 (males and females per cent) on different host
plants. Short life cycle completed with high fecundity indicated that
T. absoluta prefers tomato compared to potato and brinjal.
The morphometrics of the T. absoluta on tomato, potato and brinjal
indicated that the mean egg length was 0.47, 0.46 and 0.42 mm with width
of 0.26, 0.26 and 0.23 mm, respectively. Similarly, the mean length and width
of I, II, III and IV instar larvae was 1.53, 1.34, 1.25 mm and 0.18, 0.17, 0.15
xiii
mm; 2.63, 2.51, 2.37 mm and 0.38, 0.35, 0.33 mm; 4.16, 3.83, 3.52 mm and
0.65, 0.56, 0.56 mm; 7.52, 6.82, 6.41 mm and 1.11, 1.01, 0.93 mm,
respectively. The mean length and width of pupa was 4.51, 4.42, 4.22 mm and
1.27, 1.23, 1.21 mm, respectively. The mean length and width of adult was
10.15, 9.93, 9.05 mm and 1.79, 1.74, 1.71 mm on tomato, potato and brinjal.
The mean width of head capsule of I, II, III and IV instar larvae on
tomato, potato and brinjal was 0.17, 0.14 and 0.11 mm; 0.27 0.25 and 0.22
mm; 0.41, 0.36 and 0.35 mm and 0.72, 0.65 and 0.64 mm, respectively.
Biology of the predator, N. tenuis on T. absoluta revealed that egg
period as 6.97 days. The number of nymphal instars was five. The duration
of I, II, III, IV and V instar nymphs was 2.71, 3.09, 2.83, 3.06 and 2.76
days, respectively and total nymphal period was 14.48 days. The longevity
of adult was 7.43 days. The total life period was observed 28.89 days when
fed on T. absoluta.
The feeding potential of N. tenuis was recorded on eggs, first, second
and third instar larvae of T. absoluta . The mean predatory potential of I, II,
III, IV and V instar nymphs of N. tenuis on egg, I, II and III instar larvae of
T. absoluta was 1.25, 0.75, 0.25 and 0.25; 1.50, 1.25, 1.25 and 0.75; 2.50,
2.00, 1.75 and 1.00; 2.75, 1.50, 1.50 and 0.75 and 3.25, 1.25, 1.25 and
0.50, respectively. Average consumption capacity of the predatory adult on
eggs, I, II and III instar larvae of tomato pinworm was 4.25, 1.00, 1.00 and
0.50, respectively.
The nymphs and adult of N. tenuis preferred eggs, I, II, III larval
stages of T. absoluta, with great preference to eggs. The third instar nymph
of the predator showed the greatest effect on both first instar and second
instar larvae of T. absoluta when compared to other nymphs and adults of
N. tenuis. The fourth larval instar and pupal stage of T. absoluta was not
preferred for feeding by N. tenuis.
Parasitisation of T. absoluta eggs by different species of
trichogrammatids was also investigated and found that T. achaeae was the
most effective species in parasitising the eggs of T. absoluta. Whereas,
T. japonicum showed the least preference towards the eggs of T. absoluta.
Description
D5709
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