Effects of gall damage by the introduced biocontrol agent Epiblema strenuana (Lep., Tortricidae) on the weed Parthenium hysterophorus (Asteraceae)

2008 ◽  
Vol 125 (1-2) ◽  
pp. 1-8 ◽  
Author(s):  
K. Dhileepan ◽  
R. E. C. McFadyen
Keyword(s):  
Biocontrol Agent ◽  
Parthenium Hysterophorus ◽  
Epiblema Strenuana

Diapause regulation in Zygogramma bicolorata (Coleoptera: Chrysomelidae), a biocontrol agent of Parthenium hysterophorus

2018 ◽  
Vol 38 (02) ◽  
pp. 145-158 ◽  
Author(s):  
Fazil Hasan ◽  
M. Shafiq Ansari ◽  
Mukesh K. Dhillon ◽  
Mohammad Muslim ◽  
Amarpal Singh Bhadauriya ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Low Temperatures ◽  
Biocontrol Agent ◽  
Adult Mortality ◽  
Diapause Induction ◽  
Reproductive Status ◽  
Parthenium Hysterophorus ◽  
Biotic Factors ◽  
Zygogramma Bicolorata ◽  
Potential Biocontrol Agent

AbstractZygogramma bicolorata Pallister is a potential biocontrol agent of Parthenium hysterophorus L. (Asteraceae). This study was carried out to understand the effect of abiotic (temperature and moisture) and biotic factors (age and reproductive status) on the induction and termination of diapause in Z. bicolorata. We also evaluated the effect of diapause on longevity and fecundity of Z. bicolorata. In Z. bicolorata the induction of diapause occurred between the months of July and December. No diapause was observed in May and June, which coincided with the commencement of the monsoon rains. The percentage of diapause induction in Z. bicolorata was found to increase from one generation to another as well as with the age of adults. Diapause significantly increased the fecundity of females as compared to the fecundity in pre-diapause conditions. Soil moisture (80% RH) played an important role in providing the conditions for initiation and termination of diapause. Similarly, 18.4 and 12.5% of diapause adults resumed their activity in 6 and 5 days when exposed to temperatures of 40° and 45° C for 2 h every day, respectively. Exposure of adults to low temperatures, i.e. 5° and 10° C induced 94.3 and 92.5% diapause, respectively, with no adult mortality. Thus, our findings reveal suitable conditions for preventing and inducing diapause in Z. bicolorata, which is of great importance in the suppression of P. hysterophorus. We discuss the implications of these findings in the control of P. hysterophorus.

scholarly journals Beetle on the battle: Defoliation of Parthenium hysterophorus by Zygogramma bicolorata in Kathmandu valley, Nepal

2012 ◽  
Vol 8 ◽  
pp. 100-104 ◽  
Author(s):  
Bharat Babu Shrestha ◽  
Khum Bahadur Thapa-Magar ◽  
Ambika Paudel ◽  
Uttam Babu Shrestha
Keyword(s):  
Seed Production ◽  
Biocontrol Agent ◽  
Small Population ◽  
Parthenium Hysterophorus ◽  
Plant Science ◽  
Kathmandu Valley ◽  
Invasive Weed ◽  
Zygogramma Bicolorata

Zygogramma bicolorata, a Mexican beetle, is the most widely distributed biocontrol agent of the invasive weed Parthenium hysterophorus. The occurrence and distribution of this beetle in Nepal has been poorly documented. We monitored and mapped the occurrence of this beetle in Kathmandu valley for two years from August 2009 to September 2011. A small population of the beetle was first encountered in a wasteland at Sundarighat of Kirtipur Municipality in August 2010. By September 2011, the beetle has spread over half of the valley areas where P. hysterophorus was present, but damage to the weed was appreciable only at Sundarighat. The effectiveness of biocontrolling process is likely to be limited by shorter period of defoliating activity of the beetle, prolific seed production by Parthenium round the year, and environmental pollution.doi: http://dx.doi.org/10.3126/botor.v8i0.5559 Botanica Orientalis – Journal of Plant Science (2011) 8: 100-104

Seasonal variation in the effectiveness of the leaf-feeding beetle Zygogramma bicolorata (Coleoptera: Chrysomelidae) and stem-galling moth Epiblema strenuana (Lepidoptera: Tortricidae) as biocontrol agents on the weed Parthenium hysterophorus (Asteraceae)

2003 ◽  
Vol 93 (5) ◽  
pp. 393-401 ◽  
Author(s):  
K. Dhileepan
Keyword(s):  
Seed Bank ◽  
Negative Impact ◽  
Soil Seed Bank ◽  
Summer Rainfall ◽  
Biocontrol Agents ◽  
Parthenium Hysterophorus ◽  
Exclusion Experiment ◽  
Limited Impact ◽  
Zygogramma Bicolorata ◽  
Epiblema Strenuana

AbstractVariation in the effectiveness of biocontrol agents on the weed Parthenium hysterophorus L. was evaluated at two properties (Mount Panorama and Plain Creek) in Queensland, Australia for four years (1996–2000) using a pesticide exclusion experiment. At Mount Panorama, higher levels of defoliation by the leaf-feeding beetle Zygogramma bicolorata Pallister and galling by the moth Epiblema strenuana Walker in 1996–97 coincided with an above average summer rainfall, but in the following three years with below average summer rainfall the defoliation and galling levels were significantly lower. Biocontrol had significant negative impact on the weed only in 1996–97 with no major impact in the following three years. At Plain Creek, galling by E. strenuana was evident in all the four years, but varied significantly between years due to non-synchrony between P. hysterophorus germination and E. strenuana emergence. At Plain Creek biocontrol had limited impact on the weed in 1996–97 and 1997–98, with no significant impact in the following two years. Over the 4-year period, defoliation and galling resulted in 70% reduction in the soil seed bank at Mount Panorama, but the reduction in the soil seed bank at Plain Creek due to galling was not significant. Effectiveness of Z. bicolorata and E. strenuana was dependent on weather conditions and as a result had only limited impact on the weed in three out of four years.

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