scholarly journals Toxic and sublethal effects of buprofezin on the whitefly parasitoid Encarsia formosa Gahan

2019 ◽  
Vol 34 (3-4) ◽  
pp. 201-209
Author(s):  
Tanja Drobnjakovic ◽  
Dejan Marcic ◽  
Mirjana Prijovic ◽  
Slobodan Milenkovic
Keyword(s):  
Acute Toxicity ◽  
Emerging Adults ◽  
Sublethal Effects ◽  
Adult Emergence ◽  
Field Testing ◽  
Precise Determination ◽  
Encarsia Formosa ◽  
Instantaneous Rate ◽  
Commercial Strain ◽  
Rate Of Increase

Acute toxicity of a buprofezin-based product (commercial product Elisa 440 SC) to pupae of the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae), and its effects on life history traits and population growth in F1 generation of a commercial strain (?Dutch? strain, D) and two local populations from Serbia (Bujanovac, B; Negotin, N) were examined in laboratory bioassays. All trials were carried out at 27?1?C temperature and 60?10% relative humidity, and under 16/8 h daylight/darkness photoperiod in four replications. In an acute toxicity bioassay, tobacco leaves carrying parasitoid pupae (20 pupae per replicate) were treated with a series of buprofezin concentrations covering a 10-90% mortality range, and mortality was calculated based on the number of emerging adults 9 days after treatment. The following LC50 (mg/l) estimates were obtained: 244.2, 281.5 and 199.5 (for B, N and D, respectively). The product based on buprofezin, applied to parasitoid pupae at concentrations within the LC50s and 95% confidence limits (264 mg/l for B and N; 220 mg/l for D), significantly prolonged the duration of juvenile development (2, 1.7 and 2.2 days for B, N and D, respectively, compared to control data). Females from all tested populations that emerged from the treated pupae and were exposed to the residual action of buprofezin lived shorter than control females (B, N and D by 1.5, 0.7 and 1.7 days, respectively). Also, females that emerged from the treated pupae achieved a significantly reduced level of parasitism (B, N and D by 11.7, 17.7 and 17.6 %, respectively), total adult emergence (B, N and D by 11.6, 17.8 and 17.8 %, respectively) and instantaneous rate of increase (B, N and D by 8.2, 6.8 and 12.5 %, respectively), compared to control. More precise determination of risks involved in the use of buprofezin requires its more detailed field testing.

scholarly journals Sublethal effects of imidacloprid on the whitefly parasitoid Ecarsia formosa Gahan

2017 ◽  
Vol 32 (3-4) ◽  
pp. 205-216 ◽  
Author(s):  
Tanja Drobnjakovic ◽  
Dejan Marcic ◽  
Mirjana Prijovic ◽  
Pantelija Peric ◽  
Slobodan Milenkovic ◽  
...  
Keyword(s):  
Acute Toxicity ◽  
Sublethal Effects ◽  
Integrated Control ◽  
Pupal Stage ◽  
Adult Emergence ◽  
Encarsia Formosa ◽  
Greenhouse Whitefly ◽  
Instantaneous Rate ◽  
Commercial Strain ◽  
Total Female

Acute toxicity of an imidacloprid-based product (Confidor 200 SL) to pupae of the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae), and its effects on life history traits and population growth in F1 generation of the surviving parasitoid females of a commercial strain (?Dutch? strain, D) and two local populations from Serbia (Bujanovac, B; Negotin, N) were examined in laboratory bioassays. All trials were carried out at 27?1?C temperature and 60?10% relative humidity, and under 16/8 h daylight/darkness photoperiod in four replications. In acute toxicity bioassays, tobacco leaves carrying parasitoid pupae were treated with a series of symmetrical concentrations (800, 400, 200, 100, 50 and 25 mg a.i./l) covering a 10-90% mortality range. The product based on imidacloprid, applied directly onto parasitoid pupae at mean lethal concentrations (LC50) determined in the acute toxicity assays (30 mg/l, 20 mg/l and 25 mg/l, for populations B, N and D, respectively), significantly affected the survival of females developed from the treated pupae, extended the duration of juvenile development (by 1.81, 1.59 and 1.73 days for populations B, N and D, respectively), significantly reduced total parasitism of females D (25.92 %), total female adult emergence in populations B (27.48 %) and D (17.92 %), and significantly reduced the instantaneous rate of increased only of females N (4.23 %). Considering the high acute toxicity of the imidacloprid product to the pupal stage of E. formosa, and significant reductions in life table and population parameters, imidacloprid is not considered compatible for simultaneous use with the parasitoid E. formosa. A more precise assessment of risks involved in the use of that insecticide requires a more detailed testing in the field. The implications of these results for the concept of integrated control of the greenhouse whitefly are discussed.

scholarly journals Acute toxity and sublethal effects of pymetrozine on the whitefly parasitoid Encarsia formosa Gahan

2020 ◽  
Vol 35 (2) ◽  
pp. 81-95
Author(s):  
Tanja Drobnjakovic ◽  
Dejan Marcic
Keyword(s):  
Sublethal Effects ◽  
Integrated Control ◽  
Pupal Stage ◽  
Adult Emergence ◽  
Encarsia Formosa ◽  
Greenhouse Whitefly ◽  
Instantaneous Rate ◽  
Rate Of Increase ◽  
Juvenile Development ◽  
Total Parasitism

Sublethal effects of a pymetrozine-based product (commercial product Chess 50 WP) on life history traits and population growth of one commercialized strain (?Dutch? strain) and two local populations (Bujanovac and Negotin) of the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae) were evaluated in laboratory bioassays. All trials were carried out at 27?1?C temperature and under 60?10 % relative humidity and 16/8 h daylight/darkness photoperiod in four replications. Longevity of wasps exposed for 48 h to residues of the pymetrozine insecticide (LC50, 280 mg a.i./l) was shorter (by 2.7-3 days) than that of control wasps. Total parasitism of Negotin wasps was significantly reduced (by 8.2 %), as well as total parasitism and adult emergence of the Dutch strain (by 7.3 and 8.2 %, respectively), compared to control wasps. The instantaneous rate of increase (ri) of surviving adult wasps was also significantly reduced (by 6.6, 6.3 and 7.6 % in populations Negotin, Bujanovac and Dutch strain, respectively). Direct treatment of wasps at their pupal stage (LC50, 300 mg a.i./l) reduced total parasitism of Negotin wasps (by 8 %), and reduced ri levels, but the reduction was significant only for the Bujanovac (by 6.7 %) and Negotin (by 4.6 %) populations. Juvenile development of the parasitoid in treated pupae was significantly extended (by 0.3-1.1 days), compared to control wasps. The implications of these results on integrated control of the greenhouse whitefly are discussed.

Acaricidal activity and sublethal effects of the microbial pesticide spinosad on Tetranychus urticae (Acari: Tetranychidae)

2017 ◽  
Vol 22 (10) ◽  
pp. 1748 ◽  
Author(s):  
Irena Međo ◽  
Bojan Stojnić ◽  
Dejan Marčić
Keyword(s):  
Population Growth ◽  
Tetranychus Urticae ◽  
Sublethal Effects ◽  
Intrinsic Rate ◽  
Intrinsic Rate Of Increase ◽  
Instantaneous Rate ◽  
Leaf Discs ◽  
Rate Of Increase ◽  
Female Longevity ◽  
Microbial Pesticide

Laboratory bioassays were conducted to evaluate the toxicity of the microbial pesticide spinosad to different life stages of the two-spotted spider mite, Tetranychus urticae Koch, as well as its sublethal effects on reproduction and population growth of this important mite pest. The biopesticide was applied to bean primary leaves or leaf discs carrying spider mites using a Potter spray tower (2.7 mg/cm2 aqueous deposit). The following LC50 and LC90 (mg/L) estimates for motile stages were obtained in acute toxicity bioassays: 27.52 and 116.72 (larvae), 36.55 and 136.20 (protonymphs), 82.76 and 721.28 (female deutonymphs), and 61.47 and 457.21 (adult females). Spinosad showed no significant ovicidal action: toxic effect observed after spraying eggs (LC50 = 105.78 mg/L, LC90 = 596.95 mg/L) was the result of its residual action on larvae that hatched from the treated eggs. The effects of spinosad on life history traits and population growth of adult female survivors from treatments with 240, 120 and 60 mg/L were evaluated in two successive 7-day bioassays on untreated leaf discs. In the first bioassay, females that survived treatments as 24 h old eggs and completed their juvenile development on treated leaves had significantly lower gross fecundity, net fecundity and instantaneous rate of increase (ri) but the reduction was merely 4–6%, 9–11%, and 2–3%, respectively. Female longevity was significantly reduced (approximately by half a day) only after treatment with 240 mg/L. In the second bioassay, in which females were treated during their pre-ovipositional period, the treatments with 240 and 120 mg/L significantly reduced their gross fecundity (16–17%), net fecundity (28–31%), ri values (8–9%) and female longevity (approximately by one day). Spinosad effects on the intrinsic rate of increase (rm) and other demographic parameters were evaluated in two successive bioassays in which life tables were constructed for females that survived treatment with 120 mg/L at the egg stage (first demographic bioassay) or pre-ovipositional period (second demographic bioassay). In the first bioassay, the intrinsic rate of increase was significantly higher in treated (rm = 0.278) than control mites (rm = 0.267) as a result of higher net fertility at the beginning of reproduction of treated females. In the second bioassay, treated females had significantly lower rm than control females (0.254 and 0.283, respectively). The results obtained in this study indicate that spinosad, applied against insect pests (at field relevant rates of 60–240 mg/L), could eliminate a part of T. urticae population as well, but survivors would retain a significant potential for population recovery. 

Residual and sublethal effects of fenpyroximate and pyridaben on the instantaneous rate of increase of Tetranychus urticae

2006 ◽  
Vol 25 (6) ◽  
pp. 542-548 ◽  
Author(s):  
Minsik Kim ◽  
Cheolho Sim ◽  
Dongyoung Shin ◽  
Eunho Suh ◽  
Kijong Cho
Keyword(s):  
Tetranychus Urticae ◽  
Sublethal Effects ◽  
Instantaneous Rate ◽  
Rate Of Increase

scholarly journals The effect of spiromesifen on the reproductive potential of Tetranychus urticae koch (Acari: Tetranychidae)

2009 ◽  
Vol 24 (3) ◽  
pp. 203-209 ◽  
Author(s):  
Dejan Marcic ◽  
Irena Ogurlic ◽  
Slavka Mutavdzic ◽  
Pantelija Peric
Keyword(s):  
Tetranychus Urticae ◽  
Sublethal Effects ◽  
Reproductive Potential ◽  
Instantaneous Rate ◽  
Control Value ◽  
Rate Of Increase ◽  
Significant Difference ◽  
L 51 ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch

Laboratory bioassays were conducted to evaluate the effects of spiromesifen on the fecundity, fertility and population growth of two-spotted spider mite (Tetranychus urticae Koch) after treatment of pre-ovipositing females with five acaricide concentrations: 180 mg/l (maximum recommended concentration for use in glasshouses against spider mites), 18 mg/l, 1.8 mg/l and 0.18 mg/l (the last one was discriminative for eggs and immatures in preliminary studies, i.e. produced 100% mortality of those stages) and 0.018 mg/l. After 24h exposure, the percentages of females surviving treatment without visible symptoms of poisoning were 50% (180 mg/l), 45% (18 mg/l), 51% (1.8 mg/l), 74% (0.18 mg/l), 96% (0.018 mg/l) and 98% (0 mg/l). Over the first four days after treatment, the females that survived 180 mg/l and 18 mg/l laid no eggs. The total number of eggs laid after treatment with these two concentrations was reduced to less than 2% against the control by the end of the trial. The females that survived 1.8 mg/l laid 50% less eggs, compared to the control, while the number of eggs laid by the females treated with 0.18 mg/l and 0.018 mg/l were 19% and 4% lower, respectively. Over the initial four days, egg hatch rates in treatments were 73-87%, and 92-93% in the control. Significant statistical differences between gross fecundity (FCg) and gross fertility (FTg) values in the control and treatments were detected for females surviving 180 mg/l, 18 mg/l and 1.8 mg/l. On the other hand, only the net fertility (FTn) value of females treated with 0.018 mg/l showed no statistically significant difference from the control value. Treatments with 180 mg/l and 18 mg/l significantly reduced the instantaneous rate of increase (ri) 6, 8 and 10 days after treatment, compared to the control. The negative ri values in those treatments indicated a declining population. Sublethal effects of spiromesifen and its impact on T. urticae management are discussed.

scholarly journals Effects of spirodiclofen on the reproductive potential of two-spotted spider mite (Acari: Tetranychidae) ovipositing females

2009 ◽  
Vol 61 (4) ◽  
pp. 777-785 ◽  
Author(s):  
D. Marcic ◽  
Irena Ogurlic ◽  
P. Peric
Keyword(s):  
Spider Mite ◽  
Population Decline ◽  
Survival Rates ◽  
Reproductive Potential ◽  
Adult Emergence ◽  
Egg Laying ◽  
Instantaneous Rate ◽  
Rate Of Increase ◽  
Survival And Reproduction ◽  
Two Spotted Spider Mite

A laboratory bioassay was conducted to evaluate the effects of spirodiclofen on the survival and reproduction of young and mated females of two-spotted spider mite (Tetranychus urticae Koch). The females were sprayed with a series of acaricide concentrations (96, 48, 24, 12, and 6 mg/l) 24-30 h after adult emergence, i.e., at the age most likely to exhibit dispersal behavior and close to their reproductive maximum. The proportions of T. urticae females that survived treatment without symptoms of poisoning were concentration-dependent, ranging between 0.41 and 0.88 (0.96 in the control). With the exception of females that survived 6 mg/l, fecundity of the treated female mites was strongly affected during the exposure, compared to the control. The mean daily fecundity (EL) and mean daily fertility (EH) of surviving females, transferred daily to new leaf disks over the following five days, significantly decreased as spirodiclofen concentrations increased. In treatments with 6 mg/l and 12 mg/l, only the latter concentration significantly reduced both EL and EH, compared to the control. In females that survived 24 mg/l and 48 mg/l, these life history parameters were reduced by over 90%, while treatment with 96 mg/l completely terminated egg-laying. The treated females lived for a significantly shorter time than untreated ones, with the exception of females that survived 6 mg/l. Compared to the control females, gross fecundity (GL) and gross fertility (GH) of the treated females were strongly reduced on the first and second day; from the third day onward, females treated with the lowest concentrations achieved marked recovery, their GL and GH going even above the values in the control. However, net fecundity (NL) and net fertility (NH) of all treated females decreased considerably throughout the trial, indicating that survival rates of these females were lower, compared to the control. Calculated as total sums of gross and net daily schedules within five days, fecundity and fertility significantly decreased as spirodiclofen concentration increased. The two lowest concentrations failed to achieve a significant reduction of GL, while GH, NL, and NH were significantly lower than control values starting with the females treated with 6 mg/L. A high percentage of unhatched eggs, especially during the initial two days after treatment (35-100%), further contributed to the significant reduction in fertility of the females treated with spirodiclofen. All concentrations of spirodiclofen significantly reduced the instantaneous rate of increase. Regression analysis showed a linear population decline with increased acaricide concentrations (y = 1.13 - 0.24x; R2 = 0.91, p < 0.05).

scholarly journals Laboratory and microcosm experiments reveal contrasted adaptive responses to ammonia and water mineralisation in aquatic stages of the sibling species Anopheles gambiae (sensu stricto) and Anopheles coluzzii

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Nwamaka Oluchukwu Akpodiete ◽  
Frédéric Tripet
Keyword(s):  
West Africa ◽  
Anopheles Gambiae ◽  
Emerging Adults ◽  
Sibling Species ◽  
Adult Emergence ◽  
Ecological Speciation ◽  
Sensu Stricto ◽  
Rice Fields ◽  
Anopheles Coluzzii ◽  
Phenotypic Quality

Abstract Background The sibling species of the malaria mosquito, Anopheles gambiae (sensu stricto) and Anopheles coluzzii co-exist in many parts of West Africa and are thought to have recently diverged through a process of ecological speciation with gene flow. Divergent larval ecological adaptations, resulting in Genotype-by-Environment (G × E) interactions, have been proposed as important drivers of speciation in these species. In West Africa, An. coluzzii tends to be associated with permanent man-made larval habitats such as irrigated rice fields, which are typically more eutrophic and mineral and ammonia-rich than the temporary rain pools exploited by An. gambiae (s.s.) Methods To highlight G × E interactions at the larval stage and their possible role in ecological speciation of these species, we first investigated the effect of exposure to ammonium hydroxide and water mineralisation on larval developmental success. Mosquito larvae were exposed to two water sources and increasing ammonia concentrations in small containers until adult emergence. In a second experiment, larval developmental success was compared across two contrasted microcosms to highlight G × E interactions under conditions such as those found in the natural environment. Results The first experiment revealed significant G × E interactions in developmental success and phenotypic quality for both species in response to increasing ammonia concentrations and water mineralisation. The An. coluzzii strain outperformed the An. gambiae (s.s.) strain under limited conditions that were closer to more eutrophic habitats. The second experiment revealed divergent crisscrossing reaction norms in the developmental success of the sibling species in the two contrasted larval environments. As expected, An. coluzzii had higher emergence rates in the rice paddy environment with emerging adults of superior phenotypic quality compared to An. gambiae (s.s.), and vice versa, in the rain puddle environment. Conclusions Evidence for such G × E interactions lends support to the hypothesis that divergent larval adaptations to the environmental conditions found in man-made habitats such as rice fields in An. coluzzii may have been an important driver of its ecological speciation.

Acute toxicity, accumulation and sublethal effects of four neonicotinoids on juvenile Black Tiger Shrimp (Penaeus monodon)

Chemosphere ◽  
2021 ◽  
Vol 275 ◽  
pp. 129918
Author(s):  
Peter Butcherine ◽  
Brendan P. Kelaher ◽  
Matthew D. Taylor ◽  
Corinne Lawson ◽  
Kirsten Benkendorff
Keyword(s):  
Acute Toxicity ◽  
Sublethal Effects ◽  
Penaeus Monodon ◽  
Black Tiger Shrimp ◽  
Tiger Shrimp

Acute toxicity and sublethal effects of ammonia and nitrite for juvenile cobia Rachycentron canadum

Aquaculture ◽  
2007 ◽  
Vol 271 (1-4) ◽  
pp. 553-557 ◽  
Author(s):  
Ricardo V. Rodrigues ◽  
Michael H. Schwarz ◽  
Brendan C. Delbos ◽  
Luı˙s A. Sampaio
Keyword(s):  
Acute Toxicity ◽  
Sublethal Effects ◽  
Rachycentron Canadum
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