Conflicts between a Fungal Entomopathogen, Zoophthora radicans, and Two Larval Parasitoids of the Diamondback Moth

2000 ◽  
Vol 76 (2) ◽  
pp. 85-94 ◽  
Author(s):  
Michael J Furlong ◽  
Judith K Pell
Keyword(s):  
Diamondback Moth ◽  
Larval Parasitoids ◽  
Fungal Entomopathogen ◽  
Zoophthora Radicans

Serine proteases and metalloproteases associated with pathogenesis but not host specificity in the Entomophthoralean fungus Zoophthora radicans

2006 ◽  
Vol 52 (6) ◽  
pp. 550-559 ◽  
Author(s):  
J Xu ◽  
D Baldwin ◽  
C Kindrachuk ◽  
D D Hegedus
Keyword(s):  
Serine Protease ◽  
Host Specificity ◽  
Serine Proteases ◽  
Pathogenic Fungus ◽  
Diamondback Moth ◽  
Expression Patterns ◽  
Serial Passage ◽  
Infection Process ◽  
Original Strain ◽  
Zoophthora Radicans

The protease activity of a Zoophthora radicans strain that was highly infective toward Pieris brassicae (cabbage butterfly) larvae was compared with that of isogenic strains that were adapted to Plutella xylostella (diamondback moth) larvae through serial passage. All strains produced three distinct serine proteases ranging in size from 25 to 37 kDa; however, the original strain from P. brassicae also produced large amounts of an approximately 46 kDa metalloprotease. Subsequently, a cDNA encoding a 43 kDa (mature enzyme) zinc-dependent metalloprotease, ZrMEP1, was isolated from the original fungal strain and most likely corresponds to the 46 kDa protease observed with in-gel assays. ZrMEP1 possessed characteristics of both the fungalysin and thermolysin metalloprotease families found in some pulmonary and dermal pathogens. This is the first report of this type of metalloprotease from an entomo pathogenic fungus. A cDNA encoding a trypsin-like serine protease, ZrSP1, was also identified and was most similar to a serine protease from the plant pathogen Verticillium dahliae. In artificial media, ZrMEP1 and ZrSP1 were found to be differentially responsive to gelatin and catabolite repression in the fungal strains adapted to P. brassicae and P. xylostella, but their expression patterns within infected larvae were the same. It appears that while these proteases likely play a role in the infection process, they may not be major host specificity determinants.Key words: Zoophthora radicans, metalloprotease, serine protease, pathogenesis, entomopathogen, host specificity.

scholarly journals Mortality of various lepidopteran larvae infected by New Zealand Zoophthora radicans isolates from different hosts

2003 ◽  
Vol 56 ◽  
pp. 174-179
Author(s):  
M. Walter ◽  
F.J.L. Stavely ◽  
R.B. Chapman ◽  
J.K. Pell ◽  
T.R. Glare ◽  
...  
Keyword(s):  
New Zealand ◽  
Biocontrol Agent ◽  
Insect Pests ◽  
Diamondback Moth ◽  
Resting Spore ◽  
Lepidopteran Larvae ◽  
Potential Biocontrol Agent ◽  
Wide Range ◽  
Zoophthora Radicans ◽  
Lightbrown Apple Moth

Zoophthora radicans an entomophthoralean fungus is a potential biocontrol agent for a wide range of insect pests The mortality of six insect species inoculated with twelve Z radicans isolates from different hosts found in New Zealand was evaluated using a bioassay Zoophthora radicans isolates originating from the host being tested were generally but not always more effective than isolates originating from other species For example lightbrown apple moth (LBAM) was highly susceptible to isolates Z2 and Z6 from leafrollers (96 and 89 mortality respectively) but was not susceptible to any isolates from diamondback moth (DBM) (mortality lt;5 Plt;0001) DBM was highly susceptible to all isolates from DBM (gt;96 mortality) but only moderately susceptible to leafroller isolates (lt;66 Plt;0001) Although resting spore production was low overall some isolates produced more resting spores in certain hosts such as Z2 and Z6 in LBAM (Plt;0001) and Z8 and Z5 in DBM (Plt;005)

scholarly journals Parasitism of tomato fruitworm larvae in process tomatoes at Pukekohe

2005 ◽  
Vol 58 ◽  
pp. 224-228 ◽  
Author(s):  
G.P Walker ◽  
T.J.B. Herman ◽  
M.S. Qureshi ◽  
S. Winkler ◽  
A.R. Wallace
Keyword(s):  
Entomopathogenic Fungus ◽  
Total Mortality ◽  
The Other ◽  
Microplitis Croceipes ◽  
Alternative Hosts ◽  
Larval Parasitoids ◽  
Meteorus Pulchricornis ◽  
Helicoverpa Armígera ◽  
Zoophthora Radicans ◽  
Tomato Fruitworm

A process tomato trial was undertaken at Pukekohe to investigate the interactions between tomato fruitworm Helicoverpa armigera and its larval parasitoids the accidentally introduced generalist Meteorus pulchricornis and the introduced specialists Cotesia kazak and Microplitis croceipes Total mortality of larvae caused by parasitism was 75 with M pulchricornis the dominant parasitoid reared from 54 of parasitised larvae and C kazak and M croceipes reared from 33 and 13 respectively Cotesia kazak attacked smaller larvae than the other two species and was able to survive in the presence of the entomopathogenic fungus Zoophthora radicans late in the crop These results contrast with those for corresponding parasitism in Hawkes Bay where C kazak is very dominant It is concluded that the availability of alternative hosts in areas like Pukekohe is causing the displacement of C kazak there but that this is having little impact on biocontrol of this pest in tomatoes

scholarly journals Evaluation of pheromone trapping for prediction of diamondback moth infestations in vegetable brassicas

2003 ◽  
Vol 56 ◽  
pp. 180-184 ◽  
Author(s):  
G.P. Walker ◽  
A.R. Wallace ◽  
R. Bush ◽  
F.H. MacDonald ◽  
D.M. Suckling
Keyword(s):  
Diamondback Moth ◽  
Early Spring ◽  
Rapid Decline ◽  
Pheromone Traps ◽  
Food Research ◽  
Pheromone Trapping ◽  
Zoophthora Radicans ◽  
Trap Catches ◽  
Vegetable Brassica ◽  
Vegetable Brassicas

The use of pheromone traps was investigated as a monitoring tool to forewarn crop scouts of risk periods when diamondback moth (DBM; Plutella xylostella) larval numbers in crops are likely to increase to damaging levels We monitored traps at five brassica planting sites for 8 months and also counted numbers of DBM larvae on 50100 plants at each site Crops were scouted weekly and insecticide application decisions were made using the Crop amp; Food Research IPM programme Results showed that increases in moth trap catches predicted increases in larval infestations in three of four commercial crops in spring by 23 weeks and gave 2 weeks warning in four of five summer crops An epizootic of Zoophthora radicans caused a rapid decline in larval populations in mid to late January at all sites In these trials use of the IPM action thresholds led to a 75 reduction in insecticide use on vegetable brassica crops Overall pheromone traps were of limited value except in early spring because crops needed to be scouted regularly for other pests

scholarly journals Susceptibility of Diamondback moth (Plutella xylostella (L)) larvae to the entomopathogenic fungus Zoophthora radicans (Brefeld) Batko

2001 ◽  
Vol 54 ◽  
pp. 47-50 ◽  
Author(s):  
H. Yeo ◽  
J.K. Pell ◽  
M. Walter ◽  
K.S.H. Boyd-Wilson ◽  
C. Snelling ◽  
...  
Keyword(s):  
New Zealand ◽  
Plutella Xylostella ◽  
Entomopathogenic Fungus ◽  
Diamondback Moth ◽  
Field Conditions ◽  
Reference Isolate ◽  
Resting Spores ◽  
Zoophthora Radicans

The fungus Zoophthora radicans is being developed as a biopesticide for control of diamondback moth (Plutella xylostella) A series of laboratory doseresponse bioassays was used to determine the virulence of five isolates of Z radicans to diamondback moths indigenous to New Zealand A reference isolate from Malaysia was compared to four isolates from New Zealand Late second and early third instar diamondback moth larvae were exposed to discs of broccoli leaves that had previously been inoculated with increasing densities of fungal conidia Isolates from New Zealand were consistently more infective than the Malaysian isolate LC50 values ranged from 092 conidia/mm2 for isolate NW337 (New Zealand) to 697 conidia/mm2 for NW250 (Malaysia) Resting spores were found in up to 30 of the total number of larvae that succumbed to infection with the New Zealand isolates but were never found in larvae that succumbed to infection with isolate NW250 A single isolate was identified with potential for future testing under field conditions

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