scholarly journals Providing Alternative Hosts and Nectar to Aphid Parasitoids in a Plum Orchard to Determine Resource Complementarity and Distance Range Effect on Biological Control

Agronomy ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 77
Author(s):  
Louise Lérault ◽  
Elsa Clavel ◽  
Cinthya M. Villegas ◽  
Nuri Cabrera ◽  
Bruno Jaloux ◽  
...  

There are many different practices that contribute to conservation biological control, but little is known about their complementarity. We tested the effects of providing food and alternative hosts to parasitoids by intercropping a plum orchard with companion plants. Oats and vetch were intercropped into the orchard either as single-species (oats or vetch) or two-species (oats and vetch combined) intercrops within an inter-row. The trophic resources provided by these intercrops were assessed, along with the incidences of aphids and their parasitoids in plum trees. We found up to ten alternative host species provided by oats and vetch, and extrafloral nectar was available from the vetch and mixed strips. An effect of intercrop type and distance to plum trees was observed on aphid incidence during one sampling period. Parasitism rates in exclusion cages were affected by intercrop type, reaching almost 60% close to the mixed intercrop. However, no general tendency was observed upon whether oats, vetch or their mixture was associated with a lower incidence of aphids. We found no evidence that providing effective sources of food and alternative hosts for parasitoids increased aphid mortality in this study. The context-dependent efficiency of intercropping is discussed.

Author(s):  
Léna Durocher-Granger ◽  
Tibonge Mfune ◽  
Monde Musesha ◽  
Alyssa Lowry ◽  
Kathryn Reynolds ◽  
...  

AbstractInvasive alien species have environmental, economic and social impacts, disproportionally threatening livelihood and food security of smallholder farmers in low- and medium-income countries. Fall armyworm (FAW) (Spodoptera frugiperda), an invasive insect pest from the Americas, causes considerable losses on maize to smallholder farmers in Africa since 2016. The increased use of pesticides to control FAW in Africa raises concerns for health and environmental risks resulting in a growing interest in research on biological control options for smallholder farmers. In order to evaluate the occurrence of local natural enemies attacking FAW, we collected on a weekly basis FAW eggs and larvae during a maize crop cycle in the rainy season of 2018–2019 at four locations in the Lusaka and Central provinces in Zambia. A total of 4373 larvae and 162 egg masses were collected. For each location and date of collection, crop stage, the number of plants checked and amount of damage were recorded to analyse which factors best explain the occurrence of the natural enemy species on maize. Overall parasitism rates from local natural enemies at each location varied between 8.45% and 33.11%. We identified 12 different egg-larval, larval and larval-pupal parasitoid species. Location, maize growth stage, pest density and larval stage significantly affected parasitoid species occurrence. Our findings indicate that there is potential for increasing local populations of natural enemies of FAW through conservation biological control programmes and develop safe and practical control methods for smallholder farmers.


2021 ◽  
Author(s):  
Carmen Denis ◽  
JORDI RIUDAVETS ◽  
OSCAR ALOMAR ◽  
NURIA AGUSTI ◽  
HELENA GONZALEZ-VALERO ◽  
...  

Our study aimed to assess the contribution of natural parasitism due to Necremnus tutae Ribes & Bernardo (Hymenoptera: Eulophidae) to the biological control of Tuta absoluta (Meyrick) (Lepidopera:Gelechiidae) in commercial plots where an IPM program based on the use of predatory mirid bugs was implemented. During the samplings, the presence of another parasitoid was detected and, therefore, a second part of our study intended to identify this species and to evaluate the importance of its natural populations in the biological control of the pest. Leaflets with T. absoluta galleries were collected during 2017-2020 from commercial tomato plots in the horticultural production area of Catalonia (Northeast Spain), including greenhouses, open fields, and roof covered tunnels that lack side walls. In the laboratory, T. absoluta larvae were classified as ectoparasitized, alive, or dead. Reared parasitoids from ectoparasitized larvae were mostly morphologically identified as Necremnus sp. with parasitism rates that peaked in summer months with values between 9 and 15%. Some of these ectoparasitized larvae also yielded another parasitoid identified as Dolichogenidea gelechiidivoris Marsh (Hymenoptera: Braconidae) by both morphological and molecular-DNA barcoding methods. In 2020, parasitism rates due to D. gelechiidivoris that increased with season up to 22%. Our work reports for the first time in Europe the presence of the neotropical species D. gelechiidivoris adding this biocontrol agent to the resident parasitoid complex of T. absoluta in Spain.


1936 ◽  
Vol 27 (4) ◽  
pp. 677-713 ◽  
Author(s):  
C. Schweig ◽  
A. Grunberg

The work which is described in this paper was undertaken owing to the conflicting results of standard fumigation practice in Palestine as it existed up to 1932, so that it became evident that the response of the Black Scale to Palestine conditions called for investigation.Owing to the difference in climate between the Northern Coastal Plain and the Jordan Valley a series of parallel investigations had to be initiated, with the interesting results which Dr. Schweig and Mr. Grunberg have set forth.There seems little doubt that the growers in the Jordan Valley will have to change from summer to winter fumigation and that in Acre Sub-District even if the double fumigation now under trial is not practicable (and there is no reason wh y it should not be) fumigation will have to be completed by the end of July—otherwise the fruit of the last fumigated groves will be infested before the gangs can reach them. With regard to biological control, this would be pf more value for keeping down the Black Scale population on alternative hosts, such as Eucalyptus groves and roadside trees. Negotiations for the importation of Comperiella bifasciata are in progress, and if this proves possible it will be given a trial in the Jordan Valley and the Coastal Plain.It is unfortunate that the pressure of other demands on the time of a small staff precluded the investigation of the behaviour of the Black Scale in Jaffa Sub-District, but general observations show that it tends to react more in the manner of the Jordan Valley race than of that of the Northern Coastal Plain.All the orange-groves between Jaffa and Haifa are heavily infested with Aonidiella aurantii, and it will be interesting to see, in view of the observations on mutual tolerance contained in this paper, whether Black Scale spreading from Jaffa will drive out the Red Scale or fail to make headway agaipst it.


2008 ◽  
Vol 98 (3) ◽  
pp. 293-302 ◽  
Author(s):  
Z.Q. Yang ◽  
X.Y. Wang ◽  
J.R. Wei ◽  
H.R. Qu ◽  
X.R. Qiao

AbstractThe fall webworm, Hyphantria cunea (Drury) (Lepidoptera: Arctiidae), is an invasive and important pest in China. Investigations on insect natural enemies have been conducted from 1996 to 1999 in five provinces and one municipality of China in order to select effective species for biological control. Two carabid predators (Coleoptera) and 25 parasitoid species were found, among which 23 were parasitic wasps (Hymenoptera), including five hyperparasitic species and two tachinid flies (Diptera). The two carabids preyed on young larvae inside webs, two braconid wasps parasitized larvae, and 18 parasitoid species attacked the fall webworm during the pupal and/or ‘larval-pupal’ stages. Among these parasitoids, there were one genus and nine species that are new to science and four species new to China, which were described and published by the senior author Yang. The average parasitism rates of fall webworm pupae were 25.8% and 16.1% in the overwintering generation and the first generation (summer generation), respectively. These findings reveal that these natural enemies play an important role in the natural control of the pest. Chouioia cunea Yang (Hymenoptera: Eulophidae), a gregarious pupal endo-parasitoid, was recommended as a promising biological control agent against the fall webworm in China.


2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Tiziana Panzavolta ◽  
Francesco Croci ◽  
Matteo Bracalini ◽  
George Melika ◽  
Stefano Benedettelli ◽  
...  

Native parasitoids may play an important role in biological control. They may either support or hinder the effectiveness of introduced nonnative parasitoids released for pest control purposes. Results of a three-year survey (2011–2013) of the Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae) populations and on parasitism rates by native indigenous parasitoids (a complex of chalcidoid hymenopterans) in Italian chestnut forests are given. Changes in D. kuriphilus gall size and phenology were observed through the three years of study. A total of 13 species of native parasitoids were recorded, accounting for fluctuating parasitism rates. This variability in parasitism rates over the three years was mainly due to the effect of Torymus flavipes (Walker) (Hymenoptera: Torymidae), which in 2011 accounted for 75% of all parasitoid specimens yet decreased drastically in the following years. This strong fluctuation may be related to climatic conditions. Besides, our data verified that parasitoids do not choose host galls based on their size, though when they do parasitize smaller ones, they exploit them better. Consequently, ACGWs have higher chances of surviving parasitism if they are inside larger galls.


2019 ◽  
Vol 72 ◽  
pp. 280
Author(s):  
Emiliano R. Veronesi ◽  
Oluwashola Olaniyan ◽  
Stephen D. Wratten ◽  
Melanie Davidson ◽  
Chris Thompson

The tomato/potato psyllid (TPP), Bactericera cockerelli (Hemiptera, Triozidae), is an adventive psyllid in New Zealand that is a major pest of solanaceous crops and a serious threat to growers in the glasshouse industry. Worldwide, evaluation of potential biological control (BC) agents is normally conducted using single species and this is the case with some potential BC agents for TPP. However, the idea that multiple species can act synergistically remains largely untested so that is the aim of the current work, which is funded by Tomatoes New Zealand. The introduced parasitoid Tamarixia triozae is a BC agent of TPP that attacks mainly late instars. It lives for just 1 day when provided with water but can live up to 11 days (and consume more pests) when nectar in the flowers of buckwheat (Fagopyrum esculentum) is provided. In addition, another potential BC agent, the mirid bug Engytatus nicotianae, prefers young nymphal instars, while the ladybird Cleobora mellyi is voracious and consumes all instars. We are testing combinations of these species to understand the potential for synergies between and within trophic levels for better biological control.


ZooKeys ◽  
2019 ◽  
Vol 831 ◽  
pp. 49-69 ◽  
Author(s):  
Milana Mitrović ◽  
Petr Starý ◽  
Miljana Jakovljević ◽  
Andjeljko Petrović ◽  
Vladimir Žikić ◽  
...  

Species from the genus Paralipsis are obligatory endoparasitoids of root aphids in the Palaearctic. It is known that these species are broadly distributed, parasitizing various aphid hosts and showing great biological and ecological diversity. On the other hand, this group of endoparasitoids is understudied and was thought to be represented by a single species in Europe, viz., Paralipsisenervis (Nees). However, recent description of two new species indicated the possibility of cryptic speciation and recognition of additional Paralipsis species in Europe. In this research, Paralipsis specimens collected during the last 60 years from eight European countries, as well as one sample from Morocco, were subjected to molecular and morphological characterization. Newly designed genus-specific degenerative primers successfully targeted short overlapping fragments of COI of the mitochondrial DNA. Molecular analyses showed clear separation of four independent lineages, two of which are the known species P.enervis and P.tibiator, while two new species are described here, viz., P.brachycaudi Tomanović & Starý, sp. n. and P.rugosa Tomanović & Starý, sp. n. No clear specialization of the taxa to a strict root aphid host has been determined. The recognized mitochondrial lineages were distinct one from another, but with a substantial within-lineage divergence rate, clearly indicating the complexity of this group of parasitoids, on which further research is required in order to clarify the factors triggering their genetic differentiation. We reviewed literature data and new records of Paralipsisenervis aphid host associations and distributions. A key for the identification of all known Paralipsis species is provided and illustrated.


2021 ◽  
Vol 1 (1) ◽  
pp. 1-18
Author(s):  
Nader Sallam ◽  
Etik Mar'ati Achadian ◽  
Ari Kristini ◽  
Rob Magarey ◽  
Emily Deomano

We conducted monthly monitoring of lepidopterous moth borers in four sugarcane fields in Java, Indonesia, from May 2009 to May 2011. Fields sampled belonged to Pesantren Baru, Jombang Baru, Gondang Baru and Subang sugar factories. Three main moth borer species were found to inflict damage to sugarcane plantations in all regions, and these are the stalk borers Chilo sacchariphagus (Bojer) and Chilo auricilius Dudgeon and the top borer Scirpophaga excerptalis (Walker). Tetramoera (Eucosma) schistaceana (Snellen) was also encountered but only caused minor damage. Borer populations increased with plant age and reached a peak around January – May in most cases, with the onset of rainfall triggering population rise. All borers coexisted in the same plant with no evidence of competition between the two stalk borers (C. sacchariphagus and C. auricilius) over their specific feeding location (internode) or between the two stalk borers and the top borer (S. excerptalis) over the same plant. This suggests that an infestation by one species does not make the plant less desirable to be colonised by another. Parasitism rates by natural enemies were very low which reflects the challenges facing biological control efforts in Java. Knowledge generated through this project will improve our understanding of borer dynamics in South East Asia and will enhance our preparedness for potential introduction by any of these pests into Australia


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