scholarly journals Naturalized Dolichogenidea gelechiidivoris Marsh (Hymenoptera: Braconidae) complement the resident parasitoid complex of Tuta absoluta (Meyrick) (Lepidopera:Gelechiidae) in Spain

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.

2014 ◽  
Vol 54 (3) ◽  
pp. 306-307 ◽  
Author(s):  
Fariba Sohrabi ◽  
Hossein Lotfalizadeh ◽  
Hoda Salehipour

Abstract The tomato leafminer Tuta absoluta (Meyrick) is one of the most devastating pests of greenhouse and outdoor tomato crops. Since it is a newly introduced pest in Iran, there is an important need to search for its natural enemies. In the course of a survey on the natural enemies of this pest, samplings were carried out in tomato greenhouses heavily infested with the tomato leafminer, in the Borazjan region of the Bushehr province in Iran. Leaves with mines were reared in the laboratory until emergence of parasitoids. A single parasitoid species of the family Eulophidae was reared and identified as Neochrysocharis formosus (Westwood 1833). This species is reported for the first time on the tomato leafminer in Iran. Such information may help in developing biological control programs to control this serious pest.


Insects ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 68 ◽  
Author(s):  
Lakpo Koku Agboyi ◽  
Georg Goergen ◽  
Patrick Beseh ◽  
Samuel Adjei Mensah ◽  
Victor Attuquaye Clottey ◽  
...  

The fall armyworm, Spodoptera frugiperda, a moth originating from the American continent, has recently invaded most African countries, where it is seriously threatening food security as a pest of cereals. The current management methods rely heavily on the use of synthetic insecticides but there is a need for more sustainable control methods, including biological control. Surveys were conducted in two West African countries, Ghana and Benin, to determine the native parasitoid complex and assess parasitism rates of S. frugiperda. Samples of S. frugiperda eggs and larvae were collected in maize fields located in 56 and 90 localities of Ghana and Benin, respectively, from July 2018 to July 2019. Ten species were found parasitizing the pest, including two egg parasitoids, one egg–larval, five larval and two larval–pupal parasitoids. The two most abundant parasitoids in both countries were two Braconidae: the egg-larval parasitoid Chelonus bifoveolatus and the larval parasitoid Coccygidum luteum. Parasitism rates were determined in three Ghanaian regions and averages varied from 0% to 75% between sites and from 5% to 38% between regions. These data provide an important baseline for the development of various biological control options. The two egg parasitoids, Telenomus remus and Trichogramma sp. can be used in augmentative biological control and investigations should be conducted to assess how cultural practices can enhance the action of the main parasitoids, C. luteum and Ch. bifoveolatus, in the field. Understanding the parasitoid complex of S. frugiperda in Africa is also necessary before any development of classical biological controls involving the introduction of parasitoids from the Americas.


2018 ◽  
pp. 47-52

Epimedium elatum (Morren & Decne) of family Berberidaceace is a rare perennial medicinal plant, endemic to high altitude forests of Northwestern Himalayas in India. Ethnobotanically, it has been used as an ingredient for treatment of bone-joint disorders, impotence and kidney disorders in Kashmir Himalayas. Phytochemically, it is rich in Epimedin ABC and Icariin; all of these have been demonstrated to possess remarkable biological activities like PDE-5 inhibition (treatment of erectile dysfunction), anticancer, antiosteoporosis antioxidant and antiviral properties. The present investigation reports its traditional usage, comprehensive distribution and conservation status from twenty ecogeographical regions in Kashmir Himalayas, India. The species was reported from Gurez valley for the first time. Numerous threats like excessive grazing, deforestration, habitat fragmentation, tourism encroachment, landslides and excessive exploitation have decreased its natural populations in most of the surveyed habitats. Consequently, its existence may become threatened in near future if timely conservation steps are not taken immediately by concerned stakeholders involved in medicinal plant research. Moreover, use of plant tissue culture techniques is recommended for development of its in vitro propagation protocols. Therefore, introduction of this medicinal plant in botanical gardens, protected sites and development of monitoring programmes are needed for its immediate conservation in Northwestern Himalayas, India.


Author(s):  
G. Kinyanjui ◽  
F. M. Khamis ◽  
F. L. O. Ombura ◽  
E. U. Kenya ◽  
S. Ekesi ◽  
...  

Abstract Tuta absoluta (Meyrick) has become a serious menace to sustainable production of tomato in Kenya. A survey was conducted between April 2015 and June 2016 to determine its distribution, abundance, infestation, and damage levels on tomato, and associated natural enemies. Trap counts of T. absoluta moths were recorded in all surveyed 29 counties, which indicated its nationwide distribution irrespective of altitude. Tuta absoluta was present in both open fields and greenhouses. The highest moth/trap/day was 115.38 ± 15.90. Highest leaf infestation was 92.22% and the highest number of mines and larvae per leaf were 3.71 ± 0.28 and 2.16 ± 0.45, respectively. Trap captures in terms of moth/trap/day were linearly and positively related to leaf infestations in open fields (R2 = 0.81) and greenhouses (R2 = 0.61). Highest fruits’ infestation and damage were 60.00 and 59.61%, respectively, while the highest number of mines per fruit was 7.50 ± 0.50. Nesidiocoris tenuis (Reuter) and Macrolophus pygmaeus (Rambur) were identified as predators of T. absoluta larvae. Nine species of larval parasitoids were recovered from infested foliage, with a combined parasitism of 7.26 ± 0.65%. Hockeria species was the most dominant (31.25%) and accounted for 12.88 ± 1.47% parasitism. Two species of larval parasitoids, Hockeria and Necremnus were obtained from sentinel plants with an average parasitism of 1.13 ± 0.25. The overall abundance and parasitism rates of recovered natural enemies were low to effectively control the field populations of T. absoluta. These findings form the basis of researching and developing effective and sustainable management strategies for the pest.


Insects ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 471
Author(s):  
Angelica M. Reddy ◽  
Paul D. Pratt ◽  
Brenda J. Grewell ◽  
Nathan E. Harms ◽  
Ximena Cibils-Stewart ◽  
...  

Exotic water primroses (Ludwigia spp.) are aggressive invaders in aquatic ecosystems worldwide. To date, management of exotic Ludwigia spp. has been limited to physical and chemical control methods. Biological control provides an alternative approach for the management of invasive Ludwigia spp. but little is known regarding the natural enemies of these exotic plants. Herein the biology and host range of Lysathia flavipes (Boheman), a herbivorous beetle associated with Ludwigia spp. in Argentina and Uruguay, was studied to determine its suitability as a biocontrol agent for multiple closely related target weeds in the USA. The beetle matures from egg to adult in 19.9 ± 1.4 days at 25 °C; females lived 86.3 ± 35.6 days and laid 1510.6 ± 543.4 eggs over their lifespans. No-choice development and oviposition tests were conducted using four Ludwigia species and seven native plant species. Lysathia flavipes showed little discrimination between plant species: larvae aggressively fed and completed development, and the resulting females (F1 generation) oviposited viable eggs on most plant species regardless of origin. These results indicate that L. flavipes is not sufficiently host-specific for further consideration as a biocontrol agent of exotic Ludwigia spp. in the USA and further testing is not warranted.


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.


2019 ◽  
Vol 374 (1769) ◽  
pp. 20180204 ◽  
Author(s):  
Iliana Medina ◽  
Naomi E. Langmore

The spatial distribution of hosts can be a determining factor in the reproductive success of parasites. Highly aggregated hosts may offer more opportunities for reproduction but can have better defences than isolated hosts. Here we connect macro- and micro-evolutionary processes to understand the link between host density and parasitism, using avian brood parasites as a model system. We analyse data across more than 200 host species using phylogenetic comparative analyses and quantify parasitism rate and host reproductive success in relation to spatial distribution using field data collected on one host species over 6 years. Our comparative analysis reveals that hosts occurring at intermediate densities are more likely to be parasitized than colonial or widely dispersed hosts. Correspondingly, our intraspecific field data show that individuals living at moderate densities experience higher parasitism rates than individuals at either low or high densities. Moreover, we show for the first time that the effect of host density on host reproductive success varies according to the intensity of parasitism; hosts have greater reproductive success when living at high densities if parasitism rates are high, but fare better at low densities when parasitism rates are low. We provide the first evidence of the trade-off between host density and parasitism at both macro- and micro-evolutionary scales in brood parasites. This article is part of the theme issue ‘The coevolutionary biology of brood parasitism: from mechanism to pattern’.


2008 ◽  
Vol 69 (1) ◽  
pp. 125-134 ◽  
Author(s):  
Czesław Ślusarski

Attempts at Biological Control ofClavibacter michiganensissubsp.michiganensisOn Rockwool-Grown Greenhouse TomatoesTwo greenhouse experiments were conducted in which tomato plants artificially inoculated withClavibacter michiganensissubsp.michiganensis(Cmm) were grown in an open rockwool system as spring and autumn crops. Two isolates of the rhizosphere bacteria,Pseudomonas fluorescensstrain PSR21,Pseudomonas reactansstrain GGS14, a commercial biocontrol agent Aqua Bac Plus (Bacillusspp.) and a proprietary disinfectant containing QAC+Chx, applied at weekly intervals, were evaluated for their efficiency in the suppression of the bacterial canker of tomato. All treatments tested revealed to be ineffective in controlling the disease. The introduction ofCmmbacteria into the fresh rockwool in the first year of its usage resulted in a 100% death of tomato plants, whereas following an artificial inoculation of two- and three-year-old rockwool slabs withCmmbacteria dead plants amounted to 70 and 58%, respectively. This indicates that in the re-used rockwool a natural microbial suppressiveness to bacterial canker of tomato might be developed in the root zone.


2015 ◽  
Vol 13 (2) ◽  
pp. e1006 ◽  
Author(s):  
Xavier Pons ◽  
Meritxell Roca ◽  
Belén Lumbierres ◽  
Éric Lucas

<p>The multicoloured Asian ladybeetle, <em>Harmonia </em><em>axyridis</em> (Pallas), an invasive biocontrol agent introduced in North and South America, as well as in Europe for aphid control, drastically affected assemblages of native coccinellid species, local communities and people. Although the insect is common in several European countries and it was released in Spain for aphid control in 1995, no evidence of population establishment has been reported until 2011. In the present paper, 1) we summarize the records of the invasive ladybeetle in Spain and provide numerous new mentions, and 2) we follow for the first time an overwintering aggregation from autumn to spring and characterize some individual features which allow us to determine its phenology of the establishment and spreading. The results establish clearly that: 1) <em>H. axyridis</em> is (until now) restricted to Catalonia (NE Spain) but the invading process is in progress and the insect is able to occupy different habitats; 2) the ladybeetle overwinters successfully in Spain without significant natural mortality or parasitism; 3) the form <em>succinea</em> represents 73-81% of the overwintering individuals, and 4) the invasion takes probably its origin from Southern France. The potential impact of the invasion by <em>H. axyridis</em> in Spain is discussed.</p>


Sign in / Sign up

Export Citation Format

Share Document