Evaluation of Cosmolaelaps brevistilis and Stratiolaelaps scimitus (Mesostigmata: Laelapidae) as natural enemy of Bradysia aff. ocellaris (Diptera: Sciaridae)

Author(s):  
Adriane da Fonseca Duarte ◽  
Juliano Lessa Pinto Duarte ◽  
Lucas Raphael da Silva ◽  
Priscilla da Costa Gobbi ◽  
Uemerson Silva da Cunha

Bradysia species are major insect pests of protected production systems, including strawberry crops in semi-hydroponic systems. In Brazil, its management is difficult due to the absence of available effective pesticides. The aim of this study was to evaluate the predatory efficiency of two species of mites (Stratiolaelaps scimitus and Cosmolaelaps brevistilis) under laboratory conditions. The experiments were conducted at 25 ± 1ºC, 75 ± 10% RH, in dark. In the first bioassay predation potential of each mite species, one female per arena, was evaluated on eggs, larvae (2–3 instar) and pupae of B. aff. ocellaris, replicated thirty times, and predation, oviposition, and survivorship were recorded for ten days. In the second bioassay, fly emergence was used to determine control efficacy. Each predator species was assessed at different densities (2, 5, 7 and 10) with ten larvae of B. aff. ocellaris in each experimental unit, replicated eight times. Stratiolaelaps scimitus performed better than C. brevistilis in both bioassays, however, on the eggs and pupae life stages, both species were not effective. On the larvae life stage, mean daily predation rate was 8.25 and 4.45 for S. scimitus and C. brevistilis, respectively. For each predator species no significant differences in fly emergence were found at the four densities, however at all densities S. scimitus provided better control than C. brevistilis. Further studies on potted plants are needed to determine the potential of these species for B. aff. ocellaris management.

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 321
Author(s):  
Stefan Cristian Prazaru ◽  
Giulia Zanettin ◽  
Alberto Pozzebon ◽  
Paola Tirello ◽  
Francesco Toffoletto ◽  
...  

Outbreaks of the Nearctic leafhopper Erasmoneura vulnerata represent a threat to vinegrowers in Southern Europe, in particular in North-eastern Italy. The pest outbreaks are frequent in organic vineyards because insecticides labeled for organic viticulture show limited effectiveness towards leafhoppers. On the other hand, the naturally occurring predators and parasitoids of E. vulnerata in vineyards are often not able to keep leafhopper densities at acceptable levels for vine-growers. In this study, we evaluated the potential of two generalist, commercially available predators, Chrysoperla carnea and Orius majusculus, in suppressing E. vulnerata. Laboratory and semi-field experiments were carried out to evaluate both species’ predation capacity on E. vulnerata nymphs. The experiments were conducted on grapevine leaves inside Petri dishes (laboratory) and on potted and caged grapevines (semi-field); in both experiments, the leaves or potted plants were infested with E. vulnerata nymphs prior to predator releases. Both predator species exhibited a remarkable voracity and significantly reduced leafhopper densities in laboratory and semi-field experiments. Therefore, field studies were carried out over two growing seasons in two vineyards. We released 4 O. majusculus adults and 30 C. carnea larvae per m2 of canopy. Predator releases in vineyards reduced leafhopper densities by about 30% compared to the control plots. Results obtained in this study showed that the two predators have a potential to suppress the pest density, but more research is required to define appropriate predator–prey release ratios and release timing. Studies on intraguild interactions and competition with naturally occurring predators are also suggested.


2005 ◽  
Vol 34 (3) ◽  
pp. 181-187 ◽  
Author(s):  
Alan Cork ◽  
Malcolm J. Iles ◽  
Nazira Q. Kamal ◽  
J.C. Saha Choudhury ◽  
M. Mahbub Rahman ◽  
...  

Bangladesh is essentially self-sufficient in rice as a result of the successful adoption of new high-yielding varieties and irrigated summer production over traditional deep-water cultivation practices. The sustainability of the cropping system depends on farmers adopting integrated pest management (IPM) practices in preference to relying solely on insecticides for pest and disease control. Yet insecticide consumption in rice is increasing, in common with other crop-production systems in Bangladesh. It is probably only the poor economic returns from rice cultivation that prevent more widespread use of pesticides. Enlightened agrochemical companies such as Syngenta Bangladesh Limited have recognized that insecticide use in rice should be discouraged, and promote IPM options through their farmer field school (FFS) programme. This paper describes the results of a collaborative project to assist Syngenta to develop and incorporate mass trapping with sex pheromones into their FFS programme as an environmentally benign method of controlling the predominant insect pests of rice, stem borers.


1992 ◽  
Vol 28 (1) ◽  
pp. 31-39 ◽  
Author(s):  
N. Gunadi ◽  
M. J. Potts ◽  
R. Sinung-Basuki ◽  
Greta A. Watson

SummaryThree seasons of on-farm experimentation to develop potato production from botanical or true potato seed (TPS) under cool fertile conditions in West Java, Indonesia, are described. Twenty-three farmers experimented with two production systems: use of transplants, and use of seedling tubers produced in nursery beds. There was little yield difference between the systems, but an apparent progeny × system × season interaction was observed. All progenies were more resistant to late blight than the present cultivars grown from tubers. Appropriate matching of progeny and system gave seed of comparable quality with, but total yields slightly less than, certified imported seed of cv. Granola. Ware quality was slightly better than that of cv. Granola. Production costs were markedly less than for a tuber crop, making TPS ideal for small, resource-poor farmers.


Mammalia ◽  
2019 ◽  
Vol 83 (5) ◽  
pp. 415-427 ◽  
Author(s):  
Flávia P. Tirelli ◽  
Thales R.O. de Freitas ◽  
Fernanda Michalski ◽  
Alexandre R. Percequillo ◽  
Eduardo Eizirik

Abstract Accurate identification of predator species is a critical requirement to investigate their diet using faecal samples. We used non-invasive sampling and two methods of predator identification to investigate the diets of sympatric carnivores in a highly deforested region of the Brazilian Amazon. Of 108 scats, 81 could be identified at the species level using DNA sequencing and/or trichology. The former performed better than the latter (81.5% vs. 54.3% of the identified samples), and results were quite congruent (89.7% concordance in the 29 samples that could be assessed with both approaches). Nine species were identified, out of which four (crab-eating fox, ocelot, puma and jaguar) presented a sufficient number of samples to allow dietary analyses. The crab-eating fox was the most generalist (BA=0.92); ocelots focused on small- to medium-sized prey; pumas fed mostly on medium-sized items; and jaguars mostly targeted large-sized prey. A considerable overlap was observed between ocelots and pumas in all estimations (O=0.47–0.83). The presence of jaguars in the same region could be driving pumas to select medium- and small-sized prey. The results of this study highlight the importance of reliable predator identification and the need for in-depth ecological studies in areas where carnivore species are sympatric.


2021 ◽  
Vol 25 (1) ◽  
pp. 1-22
Author(s):  
MP Ali ◽  
B Nessa ◽  
MT Khatun ◽  
MU Salam ◽  
MS Kabir

The damage caused by insect pest is the continual factor for the reduction of rice production. To date, 232 rice insect pest species are identified in Bangladesh and more than 100 species of insects are considered pests in rice production systems globally, but only about 20 - 33 species can cause significant economic loss. The major goal of this study is to explore all the possible ways of developed and proposed technologies for rice insect pests management and minimize economic losses. Insect pests cause 20% average yield loss in Asia where more than 90% of the world's rice is produced. In Bangladesh, outbreak of several insects such as rice hispa, leafroller, gallmidge, stem borers and brown planthopper (BPH) occurs as severe forms. Based on previous reports, yield loss can reach upto 62% in an outbreak situation due to hispa infestation. However, BPH can cause 44% yield loss in severe infestested field. To overcome the outbreaks in odd years and to keep the loss upto 5%, it is necessary to take some preventive measures such as planting of resistant or tolerant variety, stop insecticide spraying at early establishment of rice, establish early warning and forecasting system, avoid cultivation of susceptible variety and following crop rotation. Subsequent quick management options such as insecticidal treatment for specific insect pest should also be broadcasted through variety of information systems. Advanced genomic tool can be used to develop genetically modified insect and plants for sustainable pest management. In addition, to stipulate farmers not use insecticides at early crop stgae and minimize general annualized loss, some interventions including training rice farmers, regular field monitoring, digitalization in correct insect pests identification and their management (example; BRRI rice doctor mobile app), and demonstration in farmers field. Each technology itself solely or combination of two or more or all the packages can combat the insect pests, save natural enemies, harvest expected yield and contribute to safe food production in Bangladesh. Bangladesh Rice J. 25 (1) : 1-22, 2021


2021 ◽  
Author(s):  
Huyen Bui ◽  
Robert Greenhalgh ◽  
Gunbharpur S. Gill ◽  
Meiyuan Ji ◽  
Andre H. Kurlovs ◽  
...  

AbstractMaize (Zea mays subsp. mays) yield loss from arthropod herbivory is substantial. While the basis of resistance to major insect herbivores has been comparatively well-studied in maize, less is known about resistance to spider mite herbivores, which are distantly related to insects and feed by a different mechanism. Two spider mites, the generalist Tetranychus urticae, and the grass-specialist Oligonychus pratensis, are notable pests of maize, especially during drought conditions. We assessed the resistance to both mite species of 38 highly diverse maize lines, including several previously reported to be resistant to one or the other mite species. We found that line B96, as well as its derivatives B49 and B75, were highly resistant to T. urticae. In contrast, neither these three lines, nor any others included in our study, were notably resistant to O. pratensis. Quantitative trait locus (QTL) mapping with F2 populations from crosses of B49, B75, and B96 to susceptible B73 identified a large-effect QTL on chromosome 6 as underlying T. urticae resistance in each line, with an additional QTL on chromosome 1 in B96. Genome sequencing and haplotype analyses identified B96 as the apparent sole source of resistance haplotypes. Our study identifies loci for use in maize breeding programs for T. urticae resistance, as well as to assess if the molecular-genetic basis of spider mite resistance is shared with insect pests of maize, as B96 is also among the most resistant known maize lines to several insects, including the European corn borer, Ostrinia nubilalis.Key message Maize(Zea mays subsp. mays) inbred lines B49, B75, and B96 harbor large-effect loci for resistance to the generalist spider mite Tetranychus urticae, but not the specialist Oligonychus pratensis.


2021 ◽  
Vol 34 (3) ◽  
pp. 631-639
Author(s):  
RENAN ALVES SANTOS ◽  
VINÍCIUS ORLANDI BARBOSA LIMA ◽  
TATIANNE GIZELLE MARQUES SILVA

ABSTRACT Caryocar brasiliense Camb. is a typical species from the Cerrado that represents a relevant income for the population where the fruit is produced. The ocorrence of insect pests provokes damage in the fruit and making its commercialization unfeasible. Then, this study aimed to identify the pest insect the fruit and the pit; to compare the morphological features of the fruit and pit and the damage caused by insects among mother plants and their origins and correlate the fruit and pit morphological features with the damage caused by the insects. Three different origins were evaluated, 12 mother plants by origin and ten fruit by mother plant. All the fruit were opened, checked for the insect damage and the fruit and pit morphological variables were determined. The insects that caused damage to the pequi embryo were identified as Carmenta sp. (Lepidoptera: Sesiidae) and Amblycerus sp (Coleoptera: Chrysomelidae). The probability analysis showed significant effect on the mother plants and origins for the percentage of fruit and pit attacked where the location of Laje Velha obtained the lowest rates of the insect attack. The fruit and pit of the Fruta de Leite were bigger and heavier than the others, while the correlations among the predation rate and the other morphological variables of the fruit and pit were not significant. Amblycerus sp. and Carmenta sp. may be considered potential pests of pequi, with the risk of compromising the pequizeiro populations and the regional economics.


Algorithms ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 290
Author(s):  
Kai Ma ◽  
Ming-Jun Nie ◽  
Sen Lin ◽  
Jianlei Kong ◽  
Cheng-Cai Yang ◽  
...  

Accurate identification of insect pests is the key to improve crop yield and ensure quality and safety. However, under the influence of environmental conditions, the same kind of pests show obvious differences in intraclass representation, while the different kinds of pests show slight similarities. The traditional methods have been difficult to deal with fine-grained identification of pests, and their practical deployment is low. In order to solve this problem, this paper uses a variety of equipment terminals in the agricultural Internet of Things to obtain a large number of pest images and proposes a fine-grained identification model of pests based on probability fusion network FPNT. This model designs a fine-grained feature extractor based on an optimized CSPNet backbone network, mining different levels of local feature expression that can distinguish subtle differences. After the integration of the NetVLAD aggregation layer, the gated probability fusion layer gives full play to the advantages of information complementarity and confidence coupling of multi-model fusion. The comparison test shows that the PFNT model has an average recognition accuracy of 93.18% for all kinds of pests, and its performance is better than other deep-learning methods, with the average processing time drop to 61 ms, which can meet the needs of fine-grained image recognition of pests in the Internet of Things in agricultural and forestry practice, and provide technical application reference for intelligent early warning and prevention of pests.


2007 ◽  
Vol 7 (2) ◽  
pp. 71-79
Author(s):  
Chaerani Chaerani ◽  
Bebet Nurbaeti

Efficacy Tests of Entomopathogenic Nematodes (Rhabditida:  Steinernema dan Heterorhabditis) as Non-endemic Natural Enemies of Yellow Rice stem Borer (Scirpophaga incertulas). Yellow rice stem borer (Scirpophaga incertulas) is a chronic insect pests of irrigated rice and difficult to control.  Entomopathogenic nematodes from the genus Steinernema and Heterorhabditis are promising biological control agents for this pest as their infective juveniles (IJs) are capable of seeking and infecting insect living in moist, cryptic habitat such as galleries created by stem borer larvae. Thirteen indigenous and exotic Steinernema and Heterorhabditis sprayed to rice seedlings in laboratory with nematodes at concentrations of 0.5 or 2.0×104 IJs ml-1 water caused larval mortality between 7–93%.  Further test in greenhouse on nematodes that had >50%  efficacy showed that an indigenous isolate, H. indicus INA H17, was the most effective among the tested nematodes in killing larvae or pupae (78%).  Reduction in plant damage caused by the insects could not be demonstrated as the trials was limited to potted plants. The survival ability of nematodes on rice plants was evaluated by using INA H4 as an example. A low percentage of INA H4 IJs (0.5%) persisted in inner leaf sheath until 7 days post application, while IJs on leaf surface and outer leaf sheath survived only until 2 and 48 hours post application, respectively. Improvement of application strategies including repeated spray, addition of antidessicant and adjusment of spray volume and application at damage threshold or plant critical period are deemed necessary to enhance nematode efficacy and reduce plant damage in the field.


2019 ◽  
Vol 24 (3) ◽  
pp. 508
Author(s):  
Wendy Lam ◽  
Quentin Paynter ◽  
Zhi-Qiang Zhang

Gorse, Ulex europaeus, is an invasive weed that has serious agricultural, economic and ecological impacts. Although various biological control agents have been released in New Zealand, these have showed no noticeable impact on gorse populations. One such agent, Sericothrips staphylinus, was introduced to New Zealand in 1990 and although laboratory impact studies indicated it was a highly promising gorse biological control agent, it has not been as effective as was hoped. We hypothesized this was due to predation by natural enemies. This study investigated the predation and oviposition rates of three phytoseiid mites (Amblydromalus limonicus, Amblyseius herbicolus, and Neoseiulus cucumeris) that have been found on gorse plants in New Zealand on three S. staphylinus stages (1st instar larvae, 2nd instar larvae, and prepupa) in both choice and non-choice conditions. In non-choice conditions, A. limonicus had the highest predation and oviposition rate across all three immature stages, and N. cucumeris had the lowest. Amblydromalus  limonicus, A. herbicolus, and N. cucumeris all had their highest predation rate when consuming 1st instar larvae, and their lowest predation rate when consuming prepupa. In the choice experiment, all three predatory mite species consumed their highest proportion of 1st instar larvae, and their lowest proportion of prepupae.  The oviposition rate of all three mite species in the choice experiment was similar to the oviposition rate when presented with 1st instar larvae only. The results from this study confirm that A. limonicus, A. herbicolus, and N. cucumeris can predate and reproduce on S. staphylinus 1st instar larvae, 2nd instar larvae, and prepupa. This indicates that predation may be the reason why S. staphylinus is an ineffective biocontrol agent in New Zealand. 


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