scholarly journals Bio-control efficiency of Bacillus thuringiensis (Berliner) against the citrus leaf miner, Phyllocnistis citrella Stainton (Lep., Gracillariidae) under laboratory conditions

2016 ◽  
Vol 48 (3) ◽  
pp. 355
Author(s):  
K. Saeidi ◽  
E. Saeidi

The citrus leaf miner, <em>Phyllocnistis citrella</em> Stainton (Lep., Gracillariidae), is one of the most destructive pest of citrus and related Rutaceae and ornamental plants in Iran. Larvae damage leaves by creating serpentine feeding mines, which have been lead to reduce yield. Resistance and toxicity problems derived from synthetic insecticides have made it necessary to find more effective and healthier alternatives; therefore, bio-insecticides (<em>i.e</em>., <em>Bacillus thuringiensis</em>) are becoming an important component in plant protection. The aim of the present study was to evaluate the efficiency of <em>B. thuringiensis</em> against <em>P. citrella</em>. Eight <em>B. thuringiensis</em> concentrations were used against <em>P. citrella</em> L3 on orange and mortality was recorded at 1, 4, 7 and 10 days after spraying. The results showed that <em>B. thuringiensis</em> significantly affected mortality of <em>P. citrella</em>. After 1, 4, 7 and 10 days of spraying 108 concentration of <em>B. thuringiensis</em> had significantly caused the highest mortality to the pest with 59.8, 68.4, 73.6 and 77.0%, respectively. Then the mortality percent decreased until it reached 6.5, 9.5, 39.3 and 46.7% at 101 concentration, respectively. In conclusion, the study indicated that <em>B. thuringiensis</em> is effective in controlling <em>P. citrella</em> under laboratory conditions.

2017 ◽  
Vol 18 ◽  
pp. 62 ◽  
Author(s):  
Z.D. Zartaloudis ◽  
M.D. Kalapanida ◽  
E.I. Navrozidis

In this study some selected insecticides were evaluated for their effect on gypsy moth Lymantria dispar L., (Lepidoptera: Lymantriidae) under laboratory conditions. Diflubenzuron, methoxyfenozide, triflumuron, fenoxycarb, fenoxycarb + lufenuron, Bacillus thuringiensis 50% subsp. kurstaki + Bacillus thuringiensis 50% subsp. aizawai, Bacillus thuringiensis subsp. aizawai and spinosad were used in the recommended concentration, against the 1st, 2nd, 3rd and 4th larval instars of L. dispar. The effectiveness of the above insecticides as well as the speed of action (LTime50 and LTime90) expressed in days, were examined in detail. Spinosad and methoxyfenozide presents a relatively higher speed of action in relation to the other insecticides. LTime50 of spinosad and methoxyfenozide did not differ significantly among the first three larval instars and ranged from 0 to 0.61 and 1.13 to 1.74 days, respectively. Regarding IGRs, the mixture (fenoxycarb + lufenuron) and triflumuron were the most effective in relation to the other IGRs tested. Moreover, Bacillus thuringiensis toxins were effective only against the first two larval instars.


Author(s):  
Charlotte Steinigeweg ◽  
Abdulrahim T. Alkassab ◽  
Hannes Beims ◽  
Jakob H. Eckert ◽  
Dania Richter ◽  
...  

AbstractThis study was aimed at evaluating the effect of a microbial pest-controlling product (MPCP) with the active substance Bacillus thuringiensis ssp. aizawai (strain: ABTS-1857) on adults and larvae of honeybees. To determine the contamination levels of Bt spores in different matrices, a colony-feeding study under semi-field conditions was performed. Furthermore, two chronic adult trials and a chronic larval study were conducted under laboratory conditions to test the effects of different concentrations of the plant protection product (PPP) on the development and mortality. Possible modifications of the chronic oral toxicity test were assessed by additional pollen feeding. Our results showed that Bt spores were detected in all matrices over the entire test duration in different concentrations, decreasing over time. The survival of adult bees and larvae was negatively affected in laboratory conditions after a chronic exposure to the MPCP depending on the tested concentrations. Moreover, the earliest sign of bee mortality, resulting from exposure to ABTS-1857, was recorded only after 96 h at the highest tested concentration. Pollen feeding to adults significantly increased the survival of the treated bees. In conclusion, the PPP with the Bt strain ABTS-1857 showed an effect on the mortality of adults and larvae under laboratory conditions. Further studies with Bt-based PPPs under realistic field conditions are necessary to evaluate the potential risk of those MPCPs on honeybees.


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