addition, the effect of abiotic factors such as soil texture and the temperature was
examined on pathogenicity of these nematodes. The higher concentrations of EPNs
induced greater larval mortality of D. ciliatus both in sandy loam and sand soil types,
whereas all concentrations of EPN species had lower virulence in clay loam. Also,
the larval mortality caused by both nematodes at 25 and 30
C was higher than that at
19
C. This research highlighted the performance of EPNs on a key pest in Iran and
demonstrated the feasibility of using EPNs in D. ciliatus IPM programs.
12.3.2.5 The Greenhouse Whitefly, Trialeurodes vaporariorum
Westwood, 1856 (Hemiptera: Aleyrodidae)
The greenhouse whitefly, Trialeurodes vaporariorum Westwood, 1856 (Hemiptera:
Aleyrodidae) is a cosmopolitan greenhouse pest that poses major problems for
farmers. In addition to decrease crop quality through feeding on plant phloem and
reduction of photosynthesis due to the development of sooty mold on excreted
honeydew of whitefly on leaves, this pest also can transmit plant viruses (Moreau
and Isman 2012). Also, there are concerns about the development of resistance to
pesticides in T. vaporariorum, as prompt researchers to find powerful alternative
tactics against this whitefly in IPM program. One scheme for controlling the
greenhouse pests, could be the application of EPNs in the greenhouse environment.
Rezaei et al. (2015) evaluated pathogenicity of S. feltiae and H. bacteriophora on
adults and second instar nymphs of T. vaporariorum on two different host-plants,
sweet pepper, and cucumber, under laboratory and greenhouse conditions. In laboratory tests, both life stages were susceptible to infection by EPNs, but S. feltiae had
a lower LC 50 than H. bacteriophora. In greenhouse experiments, they observed that
S. feltiae in lower concentrations than H. bacteriophora cause the same mortality in
nymphs. Furthermore, application of 250 IJ/cm
2 of S. feltiae on cucumber resulted in
the highest mortality rate (49 Æ 1.23%) of the second nymphal instar. In general, in
greenhouse trials, the mortality of second nymphal instars was significantly higher
on cucumber plant, with hairy leaf, than on pepper plant, with glabrous leaf.
Probably, the high density of trichome on the cucumber leaf surface increases
humidity, which is critical for enhancing EPN survival. Considering these promising
results, probably a foliar application of EPNs with a suitable adjuvant in combination
with selective insecticides can cause a profitable control of this greenhouse pest in
the short-term.
12.3.2.6 The Tomato Leafminer, Tuta absoluta Meyrick, 1917
(Lepidoptera: Gelechiidae)
The tomato leaf miner, Tuta absoluta Meyrick, 1917 (Lepidoptera: Gelechiidae) is
one of the most devastating tomato pests. After its initial tracing in eastern Spain in
2006, it rapidly invaded other European countries and extended throughout the
Mediterranean basin. In Iran, T. absoluta reported for the first time from Urmia,
12 Entomopathogenic and Insect Parasitic Nematodes
491
examined on pathogenicity of these nematodes. The higher concentrations of EPNs
induced greater larval mortality of D. ciliatus both in sandy loam and sand soil types,
whereas all concentrations of EPN species had lower virulence in clay loam. Also,
the larval mortality caused by both nematodes at 25 and 30
C was higher than that at
19
C. This research highlighted the performance of EPNs on a key pest in Iran and
demonstrated the feasibility of using EPNs in D. ciliatus IPM programs.
12.3.2.5 The Greenhouse Whitefly, Trialeurodes vaporariorum
Westwood, 1856 (Hemiptera: Aleyrodidae)
The greenhouse whitefly, Trialeurodes vaporariorum Westwood, 1856 (Hemiptera:
Aleyrodidae) is a cosmopolitan greenhouse pest that poses major problems for
farmers. In addition to decrease crop quality through feeding on plant phloem and
reduction of photosynthesis due to the development of sooty mold on excreted
honeydew of whitefly on leaves, this pest also can transmit plant viruses (Moreau
and Isman 2012). Also, there are concerns about the development of resistance to
pesticides in T. vaporariorum, as prompt researchers to find powerful alternative
tactics against this whitefly in IPM program. One scheme for controlling the
greenhouse pests, could be the application of EPNs in the greenhouse environment.
Rezaei et al. (2015) evaluated pathogenicity of S. feltiae and H. bacteriophora on
adults and second instar nymphs of T. vaporariorum on two different host-plants,
sweet pepper, and cucumber, under laboratory and greenhouse conditions. In laboratory tests, both life stages were susceptible to infection by EPNs, but S. feltiae had
a lower LC 50 than H. bacteriophora. In greenhouse experiments, they observed that
S. feltiae in lower concentrations than H. bacteriophora cause the same mortality in
nymphs. Furthermore, application of 250 IJ/cm
2 of S. feltiae on cucumber resulted in
the highest mortality rate (49 Æ 1.23%) of the second nymphal instar. In general, in
greenhouse trials, the mortality of second nymphal instars was significantly higher
on cucumber plant, with hairy leaf, than on pepper plant, with glabrous leaf.
Probably, the high density of trichome on the cucumber leaf surface increases
humidity, which is critical for enhancing EPN survival. Considering these promising
results, probably a foliar application of EPNs with a suitable adjuvant in combination
with selective insecticides can cause a profitable control of this greenhouse pest in
the short-term.
12.3.2.6 The Tomato Leafminer, Tuta absoluta Meyrick, 1917
(Lepidoptera: Gelechiidae)
The tomato leaf miner, Tuta absoluta Meyrick, 1917 (Lepidoptera: Gelechiidae) is
one of the most devastating tomato pests. After its initial tracing in eastern Spain in
2006, it rapidly invaded other European countries and extended throughout the
Mediterranean basin. In Iran, T. absoluta reported for the first time from Urmia,
12 Entomopathogenic and Insect Parasitic Nematodes
491