Dynamics of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) attacking cotton in the coastal plain of Israel

1980 ◽  
Vol 70 (2) ◽  
pp. 213-219 ◽  
Author(s):  
D. Gerling ◽  
U. Motro ◽  
R. Horowitz
Keyword(s):  
Bemisia Tabaci ◽  
Natural Enemies ◽  
Coastal Plain ◽  
Growth Pattern ◽  
Parasite Species ◽  
Host Population ◽  
Percentage Parasitism ◽  
Untreated Cotton ◽  
Eretmocerus Mundus ◽  
Parasite Populations

AbstractThe dynamics of Bemisia tabaci (Gennadius) were followed during two years in treated and untreated cotton fields in three locations in Israel. Two parasite species, Encarsia lutea (Masi) and Eretmocerus mundus Merc., were the only important natural enemies, but percentage parasitism did not rise with increase in the host population. The whiteflies reached peak populations at the end of the summer. Their distribution upon the plants was not uniform, rather, they tended to concentrate on a few leaves. The leaf bearing the maximal population was the sixth or seventh until mid-July. From then on, its location was variable according to the growth pattern of the foliage. Insecticide treatments, in particular with aldicarb, resulted in depression of both whitefly and parasite populations, but neither was exterminated.

scholarly journals Effects of buprofezin and imidacloprid on the functional response of Eretmocerus mundus Mercet

2014 ◽  
Vol 50 (No. 3) ◽  
pp. 145-150 ◽  
Author(s):  
F. Sohrabi ◽  
P. Shishehbor ◽  
M. Saber ◽  
M.S. Mosaddegh
Keyword(s):  
Functional Response ◽  
Bemisia Tabaci ◽  
Natural Enemies ◽  
Attack Rate ◽  
Sublethal Effects ◽  
Handling Time ◽  
Type Ii ◽  
Type Iii ◽  
Eretmocerus Mundus

Eretmocerus mundus Mercet is one of the key natural enemies of Bemisia tabaci (Gennadius). In this study, the sublethal effects of LC<sub>25</sub> of imidacloprid and field-recommended concentration of buprofezin on the functional response of E. mundus to different densities of second instar B. tabaci nymphs were evaluated. The results revealed a type III functional response in the control and imidacloprid treatment. The type III functional response was altered into a type II by buprofezin. Although imidacloprid did not alter the type of functional response of E. mundus compared to the control, it negatively affected the handling time and maximum attack rate of the parasitoid. Therefore, the use of this insecticide should be evaluated carefully in IPM programs.

Do different parasite species interact in their effects on host fitness? A case study on parasites of the amphipod Paracalliope fluviatilis

Parasitology ◽  
2011 ◽  
Vol 138 (9) ◽  
pp. 1176-1182 ◽  
Author(s):  
C. A. RAUQUE ◽  
R. A. PATERSON ◽  
R. POULIN ◽  
D. M. TOMPKINS
Keyword(s):  
Parasite Species ◽  
Low Frequency ◽  
Host Population ◽  
Interactive Effects ◽  
Population Means ◽  
Significant Relationships ◽  
Coitocaecum Parvum ◽  
Paracalliope Fluviatilis ◽  
Generally True

SUMMARYThere is a gap in our understanding of the relative and interactive effects of different parasite species on the same host population. Here we examine the effects of the acanthocephalan Acanthocephalus galaxii, an unidentified cyclophyllidean cestode, and the trematodes Coitocaecum parvum and Microphallus sp. on several fitness components of the amphipod Paracalliope fluviatilis, using a combination of infection surveys and both survival and behavioural trials. In addition to significant relationships between specific parasites and measures of amphipod survival, maturity, mating success and behaviour, interactions between parasite species with respect to amphipod photophilia were also significant. While infection by either A. galaxii or C. parvum was associated with increased photophilia, such increases were negated by co-infection with Microphallus sp. We hypothesize that this is due to the more subtle manipulative effect of A. galaxii and C. parvum being impaired by Microphallus sp. We conclude that the low frequency at which such double infections occur in our sampled population means that such interactions are unlikely to be important beyond the scale of the host individual. Whether or not this is generally true, implying that parasitological models and theory based on single parasite species studies do generally hold, requires cross-species meta-analytical studies.

scholarly journals The role of drugs in the control of parasitic nematode infections: must we do without?

Parasitology ◽  
1997 ◽  
Vol 114 (7) ◽  
pp. 137-144 ◽  
Author(s):  
M. H. ROOS
Keyword(s):  
Broad Spectrum ◽  
Molecular Mechanisms ◽  
Parasite Species ◽  
Parasitic Nematode ◽  
New Drugs ◽  
Pharmaceutical Companies ◽  
Parasitic Helminths ◽  
Parasite Populations ◽  
Drug Resistant Parasite

Parasitic helminths (worms) cause serious infectious diseases in humans and domestic animals. Control of these infections relies mostly on chemotherapeutics (the anthelmintics), but resistance has developed against most of these broad-spectrum drugs in many parasite species. These resistant parasites are being used to elucidate the molecular mechanisms of drug resistance and drug action. This has led to the development of sensitive assays to detect resistant parasites, but this has not delayed the emergence of additional drug resistant parasite populations. Therefore, as development of new drugs by pharmaceutical companies is slow, we may have to be prepared for a time when broad-spectrum drugs are no longer effective, especially against worms of sheep.

Improvement on Natural Enemies of Bemisia tabaci (Hemiptera: Aleyrodidae) Using Extracts of Agrimonia pilosa

2019 ◽  
Vol 112 (4) ◽  
pp. 1581-1586
Author(s):  
Huifang Guo ◽  
Yufeng Qu
Keyword(s):  
Biological Control ◽  
Bemisia Tabaci ◽  
Natural Enemies ◽  
Insect Pests ◽  
Ethanol Extract ◽  
Pathogenic Fungi ◽  
Melia Azedarach ◽  
Encarsia Formosa ◽  
Ethanol Extracts ◽  
And Control

Abstract Compared with the numerous natural enemies against insect pests that have been identified, the commercialization of natural biological control resources remains very limited. To increase the use of natural enemies for biological control, determining how to improve the low efficacy, slow speed, and high cost of natural enemies is very important. Mediterranean species of The whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodoidea), increasingly threatens many crops in China, and control primarily depends on chemical insecticides. Here, the effect of ethanol extracts from two plants, Agrimonia pilosa (Ledeb) (Rosales: Rosaceae) and Melia azedarach (Linn) (Meliaceae: Melia), on predominant natural enemies of B. tabaci was investigated using a leaf dipping or spraying method. The results showed that the ethanol extract of A. pilosa significantly improved the infectivity of the fungus Isaria javanica (Friedrichs & Bally) (Ascomycota: Hypocreales), and the mortality of whiteflies caused by the combination of fungus (105 spores/mL) with the extract of A. pilosa (2 mg/mL dried powder of A. pilosa containing 0.0942 mg/mL total polyphenols) was 81.6%, which was significantly higher than that caused by the fungus only. However, the ethanol extract of M. azedarach had no effect on fungus infectivity. Additionally, insecticide tolerance of the predator Pardosa pseudoannulata was also significantly improved by the extract of A. pilosa. The longevity of the parasitoid Encarsia formosa was not affected by the extracts. These findings indicate that the extract of A. pilosa played a dual role that included improving pathogenic fungi infectivity and insecticidal tolerance of a predator and thus could be a synergist in the biological control of B. tabaci.

scholarly journals Can Generalist Predators Control Bemisia tabaci?

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 823
Author(s):  
Arash Kheirodin ◽  
Alvin M. Simmons ◽  
Jesusa C. Legaspi ◽  
Erin E. Grabarczyk ◽  
Michael D. Toews ◽  
...  
Keyword(s):  
Bemisia Tabaci ◽  
Natural Enemies ◽  
Cropping Systems ◽  
Review Literature ◽  
Generalist Predators ◽  
Generalist Predator ◽  
Predator Species ◽  
Molecular Gut Content Analysis ◽  
Biocontrol Potential ◽  
Substantial Control

The whitefly, Bemisia tabaci, has developed resistance to many insecticides, renewing interest in the biological control of this global pest. Generalist predators might contribute to whitefly suppression if they commonly occur in infested fields and generally complement rather than interfere with specialized natural enemies. Here, we review literature from the last 20 years, across US cropping systems, which considers the impacts of generalist predators on B. tabaci. Laboratory feeding trials and molecular gut content analysis suggest that at least 30 different generalist predator species willingly and/or regularly feed on these whiteflies. Nine of these predators appear to be particularly impactful, and a higher abundance of a few of these predator species has been shown to correlate with greater B. tabaci predation in the field. Predator species often occupy complementary feeding niches, which would be expected to strengthen biocontrol, although intraguild predation is also common and might be disruptive. Overall, our review suggests that a bio-diverse community of generalist predators commonly attacks B. tabaci, with the potential to exert substantial control in the field. The key challenge will be to develop reduced-spray plans so that generalist predators, and other more specialized natural enemies, are abundant enough that their biocontrol potential is realized.

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