Effects of azadirachtin-based insecticides on the egg parasitoid Trichogramma minutum (Hymenoptera: Trichogrammatidae)

2003 ◽  
Vol 135 (5) ◽  
pp. 685-695 ◽  
Author(s):  
D.B. Lyons ◽  
B.V. Helson ◽  
R.S. Bourchier ◽  
G.C. Jones ◽  
J.W. McFarlane
Keyword(s):  
Emerging Adults ◽  
No Reduction ◽  
Control Strategies ◽  
Egg Parasitoid ◽  
Trichogramma Minutum ◽  
Female Survival ◽  
Egg Parasitism ◽  
Lepidoptera Pyralidae ◽  
Seed Extracts ◽  
Mediterranean Flour Moth

AbstractEffects of neem formulations on the reproduction and survival of the egg parasitoid Trichogramma minutum Riley were examined to assess the compatibility of the two control strategies in integrated pest management programs. A laboratory bioassay was developed for this purpose, which could be used as a model ecotoxicological system. Eggs of the Mediterranean flour moth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae), which had been treated with an acetone solution containing an azadirachtin-based formulation, were presented to individual T. minutum females. These eggs were held until parasitoids completed development and emerged from the eggs. Survival of T. minutum females 1 day after treatment, number of Mediterranean flour moth eggs parasitized, proportion of parasitized eggs from which adults emerged, and sex ratios of emerging adult parasitoids were determined. Two formulations of neem-seed extracts containing azadirachtin and a purified azadirachtin standard were tested at an operational dose and at 10 times the operational dose. At 50 g azadirachtin/ha (operational dose), no significant effects were observed on survival of parasitoid females. At 500 g azadirachtin/ha, female survival after 1 day was significantly reduced by Azatin EC and Neem EC. No reduction was evident with the 100% azadirachtin treatment, suggesting that other components of the formulations were in part responsible for the toxicity to females. Likewise, at 500 g azadirachtin/ha, the number of eggs parasitized was greatly reduced by Azatin EC and slightly reduced by Neem EC but was not reduced by an azadirachtin standard. These reductions in egg parasitism were probably due to the observed effects on female survival. At 500 g azadirachtin/ha, parasitoid developmental success was reduced by all treatments including the azadirachtin standard. Neem EC and Azatin EC at the lower dose also had a small but significant effect on developmental success. Sex ratio of emerging adults was not affected. These results indicate that azadirachtin is compatible with T. minutum during egg parasitism at operational dosages.

3.5 SUPPRESSION OF SPRUCE BUDWORM POPULATIONS BY TRICHOGRAMMA MINUTUM RILEY, 1982–1986

1990 ◽  
Vol 122 (S153) ◽  
pp. 56-81 ◽  
Author(s):  
S.M. Smith ◽  
D.R. Wallace ◽  
G. Howse ◽  
J. Meating
Keyword(s):  
Choristoneura Fumiferana ◽  
Host Density ◽  
Spruce Budworm ◽  
Mass Rearing ◽  
Egg Parasitoid ◽  
Curvilinear Relationship ◽  
Egg Masses ◽  
Trichogramma Minutum ◽  
Egg Parasitism ◽  
Release Timing

AbstractThe ability of the egg parasitoid, Trichogramma minutum Riley, to suppress outbreak populations of the spruce budworm, Choristoneura fumiferana (Clemens), was studied annually near Hearst, Ont., from 1982 through 1986. Timing of broadcast parasitoid-releases was linked to spruce budworm moth emergence and oviposition. These phenological relationships were predicted from a regression based on larval development at least 2 weeks before expected emergence; this allowed sufficient time to regulate (program) parasitoid emergence during mass-rearing. Emergence of caged spruce budworm adults was used to monitor moth eclosion in the field. Pheromone traps provided daily information on the activity of male moths and helped to synchronize the parasitoid releases with spruce budworm oviposition. Information on parasitoid activity was obtained from sentinel (laboratory-reared) and naturally occurring spruce budworm egg masses. A curvilinear relationship between the rate of parasitoid release and parasitism of sentinel egg masses was developed. Two parasitoid releases, 1 week apart, early in the oviposition period of spruce budworm, significantly increased parasitism of host eggs by 14–83% and reduced larval populations correspondingly from 42 to 82%. Single releases were less effective and increased parasitism by 0.3–52% (single ground release, 1986). Two parasitoid releases, combined with a spring application of Bacillus thuringiensis Berliner to larval populations, was the most effective strategy and resulted in 83% egg parasitism and 93% larval reduction. Release rates greater than 12–16 × 106 ♀ ♀ T. minutum per hectare were not warranted based on impact and costs. The effects of release timing, weather, host density, and parasitoid quality on the future successful use of T. minutum are discussed.

scholarly journals Natural parasitism of the second generation European corn borer eggs Ostrinia nubilalis (Hübner) (Lepidoptera, Pyralidae) by Trichogramma spp. in sweet corn fields in Vojvodina, Serbia – short communication

2017 ◽  
Vol 53 (No. 1) ◽  
pp. 50-54 ◽  
Author(s):  
Tancik Ján
Keyword(s):  
European Corn Borer ◽  
Sweet Corn ◽  
Egg Parasitoid ◽  
Trichogramma Evanescens ◽  
Corn Borer ◽  
North West ◽  
Egg Parasitism ◽  
Lepidoptera Pyralidae ◽  
Corn Fields ◽  
Natural Parasitism

Natural parasitism of the European corn borer eggs (Hübner) by Trichogramma spp. (Hymenoptera, Trichogrammatidae) was assessed in sweet corn field in north-west Serbia, region Vojvodina at the localities of Ruski Krstur, from 2004 till 2007. The rate of egg parasitism in 2004 varied from 35.89% to 73.58%. The parasitism in 2005 was lower than in 2004. On four different sampling dates in 2005 parasitism varied from 28.48% to 57.05% and averaged 39.4%. In 2006 parasitism fluctuated between 9.31 and 62.9%, averaging 32.15%. In 2007 parasitism varied from 36.8% to 54.54% and averaged 43.48%. The egg parasitoid species was identified as Trichogramma evanescens (Westwood). The study showed that this natural enemy occurred constantly in sweet corn fields but its number greatly fluctuated from year to year.

A longitudinal study of senescence in a pinniped

2002 ◽  
Vol 80 (3) ◽  
pp. 395-401 ◽  
Author(s):  
Pierre A Pistorius ◽  
Marthán N Bester
Keyword(s):  
Longitudinal Study ◽  
Adult Female ◽  
No Reduction ◽  
Marion Island ◽  
Mirounga Leonina ◽  
Elephant Seals ◽  
Reproductive Senescence ◽  
Southern Elephant Seals ◽  
Female Survival ◽  
Breeding Seasons

To measure the prevalence of senescence in southern elephant seals (Mirounga leonina Linn.) at Marion Island, changes in adult-female survival and breeding probabilities with age were quantified. Mark–recapture data that had been collected over a 17-year period were analysed using recently developed software to obtain likelihood estimates of survival and capture probabilities. With recapture effort constant over the study period, capture probabilities during the breeding seasons were used as indices of breeding probabilities. Longevity in the population was assessed from the resighting of tagged and hence known-age individuals. Less than a 1% difference between prime-age survival and post prime age survival was found over 8 cohorts of marked females. In addition, no reduction in survival of very old individuals was detected, suggesting the absence of senescence in terms of reduced survival in southern elephant seals. No evidence of reproductive senescence in terms of reduced breeding probability with age was detected. Mortality throughout the population therefore resulted in no individuals surviving to the age where physiological decline would become a mortality agent or result in failure to breed. Five percent of female southern elephant seals survived to age 10 and 0.5% to age 17.

scholarly journals Caterpillar-induced rice volatiles provide enemy-free space for the offspring of the brown planthopper

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Xiaoyun Hu ◽  
Shuangli Su ◽  
Qingsong Liu ◽  
Yaoyu Jiao ◽  
Yufa Peng ◽  
...  
Keyword(s):  
Control Strategies ◽  
Brown Planthopper ◽  
Stem Borer ◽  
Egg Parasitoid ◽  
Field Cage ◽  
Parasitism Rates ◽  
Enemy Free Space ◽  
Rice Pest ◽  
Herbivore Induced Plant Volatiles

Plants typically release large quantities of volatiles in response to herbivory by insects. This benefits the plants by, for instance, attracting the natural enemies of the herbivores. We show that the brown planthopper (BPH) has cleverly turned this around by exploiting herbivore-induced plant volatiles (HIPVs) that provide safe havens for its offspring. BPH females preferentially oviposit on rice plants already infested by the rice striped stem borer (SSB), which are avoided by the egg parasitoid Anagrus nilaparvatae, the most important natural enemy of BPH. Using synthetic versions of volatiles identified from plants infested by BPH and/or SSB, we demonstrate the role of HIPVs in these interactions. Moreover, greenhouse and field cage experiments confirm the adaptiveness of the BPH oviposition strategy, resulting in 80% lower parasitism rates of its eggs. Besides revealing a novel exploitation of HIPVs, these findings may lead to novel control strategies against an exceedingly important rice pest.

scholarly journals Impulsive Biological Pest Control Strategies of the Sugarcane Borer

2012 ◽  
Vol 2012 ◽  
pp. 1-14 ◽  
Author(s):  
Marat Rafikov ◽  
Alfredo Del Sole Lordelo ◽  
Elvira Rafikova
Keyword(s):  
Pest Control ◽  
Floquet Theory ◽  
Control Strategies ◽  
Egg Parasitoid ◽  
Asymptotically Stable ◽  
Biological Pest Control ◽  
Globally Asymptotically Stable ◽  
Larval Stages ◽  
Sugarcane Borer ◽  
Impulsive Release

We propose an impulsive biological pest control of the sugarcane borer (Diatraea saccharalis) by its egg parasitoidTrichogramma galloibased on a mathematical model in which the sugarcane borer is represented by the egg and larval stages, and the parasitoid is considered in terms of the parasitized eggs. By using the Floquet theory and the small amplitude perturbation method, we show that there exists a globally asymptotically stable pest-eradication periodic solution when some conditions hold. The numerical simulations show that the impulsive release of parasitoids provides reliable strategies of the biological pest control of the sugarcane borer.

Influence of intercropping on the abundance, distribution and parasitism of Chilo spp. (Lepidoptera: Pyralidae) eggs

1997 ◽  
Vol 87 (5) ◽  
pp. 507-513 ◽  
Author(s):  
P. Päts ◽  
B. Ekbom ◽  
H. Skovgård
Keyword(s):  
East Africa ◽  
Chilo Partellus ◽  
Field Experiments ◽  
Plant Density ◽  
Coastal Areas ◽  
Positive Density ◽  
Abundance Distribution ◽  
Significant Difference ◽  
Egg Parasitism ◽  
Lepidoptera Pyralidae

AbstractTwo of the most common and serious pests of maize and sorghum in the coastal areas of East Africa are the pyralid species, Chilo partellus (Swinhoe) and C. orichalcociliellus (Strand). Maize monocrop (with high and low plant density) and maize/cowpea mixed intercrop field experiments were conducted in Kenya to test if intercropping decreased the number of egg batches laid, altered the distribution of the egg batches and influenced egg parasitism. There was no significant difference in the number of egg batches per plant between treatments and the egg batches were randomly distributed on and among plants in most of the plots for all three treatments. There was a tendency for higher egg parasitism in the intercrop. The proportion of eggs parasitized was significantly correlated with total number of eggs per plot suggesting a positive density dependent response. It is concluded that intercropping does not affect C. partellus nor C. orichalcociliellus oviposition behaviour but egg parasitism is likely to be augmented.

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