Bacillus Thuringiensis Var Research Articles

Испан шырышты ұлуының (Arion vulgaris Moquin-Tandon, 1855) таралу аймағының географиялық кеңеюі

The article provides information about the most dangerous Spanish slimy snails that entered the territory of Kazakhstan. At the beginning of July 2020, we first met the Spanish slug (Arion vulgaris) in the Medeu State Regional Natural Park. Slimy snails predominate in the moist areas of the lower slopes of the mountains. They crowd out and replace other native animals. These species are a natural threat to local snails. Therefore, experiments were carried out on an area of 10 m2 to test biological agents against the Spanish snail (Arion vulgaris). According to the results of industrial tests, the biological preparation Bitoxibacillin (Bacillus thuringiensis var.) Showed a biological effect of 7 days — 74.9 and 7 days — 87.4 compared to the untreated control area. The biological product Aktarofit showed high biological effectiveness, providing 100% removal of Spanish mucus on the 1st day after treatment. Today, due to the annual increase in trade with foreign countries, the country has the possibility of spreading various types of pests. Therefore, to prevent these problems, further monitoring is needed to improve control of Spanish snails.

Monitoring and population characteristics of Prays oleae (Lepidoptera: Yponomeutidae) on different insecticidal treatments

The presence of olive moth (Prays oleae Bern.) and effectiveness of different control treatment against it has been conducted on 160 olive trees of Leccino variety in Istria, Croatia. The treatments were: dimethoate, Bacillus thuringiensis var. kurstaki (Bt), pyrethrins, consociation of olive and planted pyrethrum and control. Olive moth has been monitored weekly using pheromone-baited delta traps and different coloured sticky plates in 12 and eight monitoring. Moth's life stages (non-destroyed, destroyed eggs and larvae) has been counted in seven monitoring. The predator activity has been determined as the ratio of destroyed eggs in the total number of observed eggs on 50 randomly chosen samples of flowers and fruits. On pheromone traps, the maximum catch has been determined on May 15th on control, when maximum of moth's flight on control, dimethoate and pyrethrins treatments coincided in time. There were more adults detected on pheromone traps then on sticky traps (16.8 times over). With time, moth's first preference was red and then blue sticky plates. The highest number of eggs ( non-destroyed and destroyed) has been found on dimethoate on May 15th ( 2.8 ± 1.1 and 4.5 ± 1.6) and June 18th ( 0.8 ± 0.5) as a consequence of accidental high oviposition rate at dimethoate plots before treatment applications. The highest number of larvae were detected on control on July 2nd ( 2.0 ± 0.7)

The system for regulation of cotton bollworm population on tobacco in crop rotation of organic agriculture

The results of development of the control system over the population of cotton bollworm Helicoverpa armigera Hbn are presented to protect seed plantings of tobacco with the use of plant isolation. The studies were conducted in the Krasnodar Territory on a tobacco variety Yubileiny novy 142. The regulation of the cotton bollworm population on tobacco seed plantings was carried out by the method of mass capture of male pests with pheromone traps in order to change the gender balance. This was done together with the application of a biopreparation and sowing of a trap crop (corn) to attract and catch butterfl ies at an earlier stage. At a high degree of bollworm population (4–10 specimens / tobacco infl orescence) on non-isolated plants, insecticides based on baculovirus of nuclear polyhedrosis of cotton bollworm FermoVirin XC (in the doze 1.0– 4.0 g/ha) and Helicovex (0.05–0.2 l/ha) were used three times with an interval of 7 days in combination with “male vacuum”. Biological effi ciency was 38– 77 and 62–84% in reducing the number of bollworm larvae, 41–75 and 60–79% in decreasing the damage, respectively. The decrease in the number of bollworm larvae on isolated plants reached 36– 70 and 58–79%, the decrease in damage – 39–69 and 60–72%, respectively. Treatment of seed plots with virus insecticides allowed to save from 22 to 43 kg of the biological yield of tobacco seeds per 1 ha on non-isolated plants and from 21 to 51 kg on isolated plants. With a low number of hatching larvae (14 specimens / 100 plants), a single use of the preparations Bitoxibacillin (Bacillus thuringiensis var. Thuringiensis) and Lepidocide (Bacillus thuringiensis var. Kurstaki) reduced the amount of phytophage by 47–75 and 48–64%, respectively. The system is recommended for use on other crops damaged by cotton bollworm, including in organic farming technologies.

Регулювання технологічної активності штаму Bacillus Thuringiensis 87-15 в умовах глибинного культивування

Представлено наукове обґрунтування та вирішення актуальних завдань контролю і регуляції технологічної активності перспективного ентомопатогенного штаму Bacillus thuringiensis var. thuringiensis (H1) 87-15 природного типу як продуцента рідкої препаративної форми для біоконтролю фітофагів. Встановлено вплив різних поживних середовищ на продуктивність штаму №87-15 при глибинному культивуванні та позитивна динаміка утворення спор і ентомотоксичних метаболітів (титр спор на 72 годині ферментації в межах 3,6-4,5 млрд./мл культуральної рідини). Оптимізація рН середовища, температурного діапазону росту та режиму аерації під час формування мікробної маси Bacillus thuringiensis дає можливість отримувати більшу кількість біоматеріалу (рідкого концентрату) та прискорити процес отримання препаративної форми.

Conspecific and allospecific larval extracts entice mosquitoes to lay eggs and may be used in attract-and-kill control strategy

One of the strategies of integrated vector management is to lure gravid mosquitoes for surveillance purposes or to entice them to lay eggs in water containing toxins that kill the offspring (attract-and-kill or trap-and-kill). Typically, the major challenge of this approach is the development of a lure that stimulates oviposition plus a toxin with no deterrent effect. Bacillus thuringiensis var. israelensis (Bti) satisfies the latter criterion, but lures for these autocidal gravid traps are sorely needed. We observed that gravid Aedes aegypti, Ae. albopictus, and Culex quinquefasciatus laid significantly more eggs in cups with extracts from 4th-stage larvae (4 L) of the same or different species. No activity was found when 4 L were extracted with hexane, diethyl ether, methanol, or butanol, but activity was observed with dimethyl sulfoxide extracts. Larval extracts contained both oviposition stimulant(s)/attractant(s) and deterrent(s), which partitioned in the water and hexane phases, respectively. Lyophilized larval extracts were active after a month, but activity was reduced by keeping the sample at 4 °C. In the tested range of 0.1 to 1 larvae-equivalent per milliliter, oviposition activity increased in a dose-dependent manner. In field experiments, Ae. aegpti laid significantly more eggs in traps loaded with larval extracts plus Bti than in control traps with water plus Bti.

Mosquito control actions affect chironomid diversity in temporary wetlands of the Upper Rhine Valley.

The Upper Rhine Valley, a "hotspot of biodiversity" in Germany, has been treated with the biocide Bacillus thuringiensis var. israelensis (Bti) for mosquito control for decades. Previous studies discovered Bti nontarget effects in terms of severe chironomid abundance reductions. In this study, we investigated the impact of Bti on species level and addressed the community composition of the nontarget family Chironomidae by use of community metabarcoding. Chironomid emergence data were collected in three mosquito-control relevant wetland types in the Upper Rhine Valley. For all three sites the chironomid species composition, based on operational taxonomic units (OTUs), was different to varying degrees in the Bti-treated samples versus control samples, ranging from a significant 63% OTU reduction to an OTU replacement. We assumed that predatory chironomids are less prone to Bti than filter feeders, as the latter feed on floating particles leading to direct ingestion of Bti. However, a comparable percentage of predators and filter feeders (63% and 65%, respectively) was reduced in the Bti samples, suggesting that the feeding strategy is not the main driver for Bti sensitivity in chironomids. Finally, our data was compared to a three-year-old data set, indicating possible chironomid community recovery due to species recolonization a few years after the last Bti application. Considering the currently discussed worldwide insect decline we recommend a rethinking of the usage of the biocide Bti, and to prevent its ongoing application especially in nature protection reserves to enhance ecological resilience and to prevent boosting the current biodiversity loss.

Some alternatives to the chemical control of Spodoptera exigua (Hubner, 1808) in black-eyed pea

Spodoptera exigua (Hubner), is a destructive pest in different parts of the world. In this study, the effects of indoxacarb, chlorpyrifos, deltamethrin, hexaflumuron, matrin, and Bacillus thuringiensis var. kurstaki)Bt), were evaluated against S. exigua in a complete randomized block design under field conditions. Four replications were considered for each treatment. The qualitative and quantitative damages of the pest were estimated based on plant growth characteristics. The experiments were carried out in 2016 and 2017 in a pea field in Khuzestan province, Iran. Sampling of S. exigua population was conducted 1 day before treatment (DBT) and 1, 3, 5, 7 and 10 days after treatment (DAT). The results showed that indoxacarb significantly reduced oviposition in S. exigua. Chlorpyrifos and indoxacarb significantly affected larval survival shortly after treatment. However, no significant difference was observed in larval mortality among treatments 10 DAT and all were effective against larvae. The results also showed that the maximum bean pods were observed in chlorpyrifos and indoxacarb treatments, respectively. There were the most seeds in each pod in matrin, indoxacarb, chlorpyrifos and deltamethrin treatments. According to the results, Bt and matrin were effective insecticides against S. exigua larvae and can be recommended as an alternative to chemical pesticides.

The impact of pesticides used in greenhouses, on the predatory mite neoseiulus californicus (parasitiformes, phytoseiidae)

Nine commercial pesticides currently used in Russian greenhouses against pests (aphids, thrips, whiteflies) were selected to determine their toxicity to predatory mite Neoseiulus californicus McGregor in order to find out the potential use him affected by chemical treatments Vertimec (abamectin), Fitoverm (aversectin C), Clipper (bifenthrin), Novaction (malation), Oberon (spiromesifen), Bitoxibacillin (Bacillus thuringiensis var. thuringiensis), Actara (tiametoxam), Admiral (piriproxifen), Confidor (imidacloprid), Mospilan (acetamiprid). The recommended concentration of the preparation (T), half the concentration (1/2T), and a double concentration (2T) were used on the female mite in the experiments. The side effects of the pesticides applied to the predator mite were determined one, three, and five days after the application. The recommended concentration of the preparation of Vertimec, Fitoverm and Clipper showed a higher toxic effect on N. californicus femails (mortality rate 100%). The obtained data reveals the impossibility of their joint application with the release of N. californicus. The toxic effects of Mospilan, Confidor, Admiral, Actara, Bitoxibacillin and Novaktion on N. californicus females were a low level (mortality of females 0-16,6%). The present study confirms that the use of predatory mite N. californicus in combination with these pesticides prospectively in Integrated Pest Management in Russian greenhouse conditions.

Effect of Bacillus thuringiensis var. israelensis Sugar Patches on Insecticide Resistant Anopheles gambiae s.l. Adults.

Large distribution of long-lasting insecticidal nets (LLINs) and indoor residual spraying (IRS) contributed to a significant decrease in malarial mortality. Unfortunately, large insecticide resistance in malaria vectors occurred and is a threat to the future use of these control approaches. The purpose of this study was to explore a new approach for vector control. Patches containing Bacillus thuringiensis var. israelensis (Bti) solubilized Cry toxins mixed with sugar were developed and tested in the laboratory with pyrethroid-resistant Anopheles gambiae s.l. using tunnel tests. Mosquitoes were released at 6:00 p.m. into a large tunnel separated by a bed net, perforated with nine holes, from a smaller chamber with a guinea pig. Nine Bti sugar patches (BSPs) were attached to the bed net between the nine holes. Fourteen hours later (8:00 a.m.), mosquitoes were collected from the tunnel and the guinea pig chamber. Live females were kept in cups and were fed a sugar solution (5%) for 72 h and delayed mortality was followed. The results were reported as passing, blood fed and mortality rates. Mosquito populations that are resistant to the insecticides in the bed net, exhibited high mortality (60%) in the presence of the BSPs. Untreated bed nets with patches in the tunnel test killed 66-95% of the mosquitoes that landed and untreated bed nets were superior to treated bed nets. BSPs efficiently kill resistant mosquitoes that land on treated and untreated bed nets and thus could ultimately reduce the number of vector-borne malarial mosquitoes.

High-energy ball milling treatment of soybean for Bacillus thuringiensis culture media

Soybean meal has been intensively used as a substrate in culture media for several microorganisms. However, the fermentable sugar containing the soybean needs to be released from the solid matrix through different processes. Against this backdrop, the present study explores the use of high-energy ball milling as a one-step treatment method for expedited production of fermentable sugars of textured soybean. The best result is observed after only 5min of milling, obtaining 34.1 times more fermentable sugars than untreated textured soybean, and 2.5 times more than commercially used soybean meal. Notably, the textured soybean ball-milled has been used as a substrate for Bacillus thuringiensis var. kurstaki HD-73 fermentation. The cell and spore production is also compared with a standard Rowe media. The maximum cell concentration obtained in the entire fermentation process using ball-milled textured soybean media is found to be higher than the concentration obtained using the standard Rowe media. In addition, it is observed that there is a direct correlation between maximum cell production and reducing sugar concentration generated by the high-energy ball milling treatment. No fermentation inhibitors or by-products are generated during the physical treatment.

Toxicological Examinations Following Oral Administration of Bacillus thuringiensis var kurstaki Biological Insecticide in Wistar Rats

Introduction: Bacillus thuringiensis var kurstaki is one of the best known biological insecticide which is used extensively in the world. This biopesticide has been broadly used against important insect pests and vectors of animals and humans. However, the controversial data was published to date considering toxicological studies on non-target species are urgent to determine probable adverse effects and risk assessment of this biopesticide. In this research, histopathological changes, hematological and some biochemical factors were evaluated following the single dose oral administration of B. thuringiensis in rats. Materials and Methods: Twelve Wistar rats were randomly divided into 2 groups including experimental and control groups. Animals were treated orally by gavage to single dose of sub-lethal dose (5000 mg/kg) of B. thuringiensis suspension. Finally, hematological factors (WBC, RBC, Hb, HCT, MCV, MCH, MCHC and PLT), some biochemical parameters (ALT, AST, ALP, BUN and Cr) and histopathological observations were evaluated. Results: The results demonstrated that oral administration of high dose of B. thuringiensis biopesticide induced some pathological complications including congestion and inflammation in vital organs of rats such as liver, heart, lung and kidney. It also caused hematological abnormalities and biochemical alterations in the experimental animals group. Conclusions: According to the findings, it can be concluded that high dose of B. thuringiensis biopesticide can induce toxicity in rats. Therefore, further investigations including subacute and chronic are recommended.

Rice farmers\u2019 perceptions and acceptability in the use of a combination of biolarvicide (Bacillus thuringiensis var. israeliensis) and fertilizers application for malaria control and increase rice productivity in a rural district of central Tanzania

BackgroundThe use of larval source management as a supplementary intervention for malaria control has not been widely used in rural Africa due to perceived high costs and complex logistics. To reduce the cost of larviciding in rice farming communities, concurrent application of biolarvicides and fertilizer in rice fields was introduced to control malaria vectors larvae and improve rice grain yields. The present study determined rice farmers’ perceptions and acceptability in the use of a combination of biolarvicide and fertilizers in farming practices.MethodsThis was a qualitative study conducted among rice farmers at Kilangali village, south-central Tanzania. Semi-structured interviews and three focus group discussions (FGDs) were conducted with men and women who participated in the biolarvicide and fertilizer application project. The interviews and discussion focused on knowledge, attitudes and perceptions of participants on the use of the innovation in their farming practices and their willingness to pay for the innovation.ResultsA total of 40 (mean age = 38.8 ± 10.12 years) rice farmers were involved in the study. Overall, all farmers agreed that it was possible to apply the two products concurrently with minimal challenges. The trust on the safety of biolarvicides on both human and paddy health was high. Respondents reported no challenge in preparation and applying the product in their rice fields. Over half (56.6%) of the participants reported an average decrease in mosquito density in their households and a quarter (26.6%) of them reported a decrease in mosquito population in their farms. Similarly, 93.3% of the participants reported that the intervention had reduced malaria risk in their households. In general, all participants expressed willingness to contribute to a biolarvicide and fertilizer programme and to use the approach in their farming practices.ConclusionCommunity-based concurrent application of biolarvicides and fertilizer in rice fields was feasible and led to a perceived reduction in mosquito density. Willingness to pay for the larviciding/fertilizer approach was expressed by participants and they accepted to use the approach in their future farming practices. However, the impact of this approach on malaria transmission and rice grain harvest need to be evaluated in a large-scale programme.

Daily temperature variation magnifies the toxicity of a mixture consisting of a chemical pesticide and a biopesticide in a vector mosquito

While many studies on the toxicity of pesticides looked at the effects of a higher mean temperature, effects of the realistic scenario of daily temperature variation are understudied. Moreover, despite the increasing interest for the toxicity of pesticide mixtures how this is influenced by temperature has been largely ignored. We tested whether daily temperature variation (DTV) magnifies the toxicity of two pesticides with a different mode of action, the organophosphate pesticide chlorpyrifos (CPF) and the biopesticide Bacillus thuringiensis var. israelensis (Bti), and of their mixture in the vector mosquito Culex pipiens. Single exposure to CPF and Bti increased mortality and reduced female development time, and exposure to CPF also increased female wing length. DTV was not lethal and did not change the toxicity of the individual pesticides. Yet, a key novel finding was that high DTV increased the mortality of the mixture by changing the interaction between both pesticides from additive to synergistic. Given that in nature daily temperature variation is omnipresent, this is important both for vector control and for ecological risk assessment. The higher toxicity of the mixture at high DTV compared to the typically used constant test temperatures in the laboratory urges caution when evaluating the environmental impact of pesticide mixtures.

Adverse effects of mosquito control using Bacillus thuringiensis var. israelensis: Reduced chironomid abundances in mesocosm, semi-field and field studies

The ecological consequences of mosquito control using the larvicide Bacillus thuringiensis israelensis (Bti) are still a matter of debate especially when it comes to adverse effects on non-target but susceptible non-biting midges (Chironomidae). Our work aimed to assess the effects of Bti applied in operational mosquito control rates on chironomid abundances in seasonal flooded freshwater wetlands. We assessed the invertebrate community alongside with aquatic insect emergence rates in studies with increasing ecotoxicological complexity, ranging from artificial mesocosms, over a semi-field approach using enclosures to natural conditions in field studies. Study sites represented different habitats (forest, meadow, floodplain) with regularly Bti treated and untreated temporal wetlands that are located in the Upper Rhine Valley, Germany. Larval chironomids were the most affected group of organism in the altered aquatic invertebrate communities of the Bti treated pond mesocosms. The larvae of the chironomid subfamilies Chironominae and Orthocladiinae were affected by Bti field concentrations while emergence rates of Tanypodinae did not change. The Bti treatment significantly reduced the targeted mosquitoes in the mesocosm and in the field studies. At the same time, however, the application of operational Bti field rates reduced overall chironomid emergence rates to about half of the control rates. The observed abundance reductions occurred independently of the ecological complexity in the study design in artificial mesocosms as well as realistic field conditions. The considerable reduction of the abundant non-target chironomids along with mosquitoes may subsequently lead to unwanted indirect negative effects for birds, bats and other aquatic organisms feeding on midges. Hence, large-scale applications of Bti for mosquito control in seasonal wetlands should be considered more carefully. This is of special importance when these wetlands are parts of national parks, nature reserves or Natura 2000 sites that were created for the protection of nature and environmental health.

Larvicidal effects of supercritical extract of Melia azedarach and Bacillus thuringiensis var. israelensis product on late instar of Aedes aegypti (Diptera: Culicidae)

The intense use of synthetic products for the control of Aedes aegypti has led to the development of resistance and imposes health risks to other flora and fauna. This study assessed the larvicidal potential of Melia azedarach (Meliaceae) fruit extract obtained by the supercritical carbon dioxide extraction method and Bacillus thuringiensis var. israelensis (Bti) on second and third instar A. aegypti larvae under laboratory conditions. The assays were performed in disposable cups containing 100 250, 500, 750, 1,000 and 2,000 μg/ml extracts of M. azedarach, and 0.0005, 0.001, 0.0015, 0.002, and 0.0025 g/L of VectoBac WG®; the controls contained only water. Ten active larvae were added to each well, and the number of living larvae was counted each day for 72 h. Treatment efficiency was calculated using Abbott's equation. Insecticidal efficiency increased with M. azedarach extract concentration, with significant effects in the 1.000 and 2.000 μg/mL concentration range. Bti efficiency was 100 % in the first 24 h. The results indicate the possibility of A. aegypti population control using supercritical extracts of M. azedarach.

Efficacy of Bacillus thuringiensis israelensis (Bti) and four plant extracts on the mortality and development of Culex quinquefasciatus Say (Diptera: Cullicidae)

The efficacy of the bio-insecticide, Bacillus thuringiensis var. israelensis (Bti), and four plant-ethanol extracts Cinnamomum osmophloeum, Matricaria chamomilla, Seasamum indicum, and Nigella sativa was tested against larvae of filarial vector, Culex quinquefasciatus, under laboratory conditions. The Bti and extracts of N. sativa and C. osmophloeum showed the highest insecticidal activity, with LC50 values of 7.18, 14.59, and 28.87 mg/l 24 and 48 h post treatments, respectively. The extracts of M. chamomilla and S. indicum were effective. The tested extracts altered some biological aspects of Cx. quinquefasciatus, i.e., developmental periods, pupation rate, and adult emergence. Pupation rate was suppressed by Bti at 7.5 mg/l and by C. osmophloeum at 75 mg/l. In addition, the tested plant extracts exhibited various morphological abnormalities of larvae, pupae, and adults.

Herbivore-Induced Defenses in Tomato Plants Enhance the Lethality of the Entomopathogenic Bacterium, Bacillus thuringiensis var. kurstaki.

Plants can influence the effectiveness of microbial insecticides through numerous mechanisms. One of these mechanisms is the oxidation of plant phenolics by plant enzymes, such as polyphenol oxidases (PPO) and peroxidases (POD). These reactions generate a variety of products and intermediates that play important roles in resistance against herbivores. Oxidation of the catecholic phenolic compound chlorogenic acid by PPO enhances the lethality of the insect-killing bacterial pathogen, Bacillus thuringiensis var. kurstaki (Bt) to the polyphagous caterpillar, Helicoverpa zea. Since herbivore feeding damage often triggers the induction of higher activities of oxidative enzymes in plant tissues, here we hypothesized that the induction of plant defenses would enhance the lethality of Bt on those plants. We found that the lethality of a commercial formulation of Bt (Dipel® PRO DF) on tomato plants was higher if it was applied to plants that were induced by H. zea feeding or induced by the phytohormone jasmonic acid. Higher proportions of H. zea larvae killed by Bt were strongly correlated with higher levels of PPO activity in the leaflet tissue. Higher POD activity was only weakly associated with higher levels of Bt-induced mortality. While plant-mediated variation in entomopathogen lethality is well known, our findings demonstrate that plants can induce defensive responses that work in concert with a microbial insecticide/entomopathogen to protect against insect herbivores.

Combined larvicidal and adulticidal treatments to control Culicoides biting midges (Diptera: Ceratopogonidae): Results of a pilot study

Culicoides biting midges can transmit viruses such as bluetongue virus and Schmallenberg virus to ruminants and African horse sickness virus to equines. The control of Culicoides population can be based on physical and/or chemical methods. This study aims to evaluate the efficacy of larvicides and adulticides combined treatments to control the vector Culicoides populations. Field trials have been conducted during 2014 on seven farms in northern Sardinia (Italy). Three insecticide treatments (larvicides and adulticides) have been carried out on three farms, whereas four farms remained unsprayed as untreated controls. For the larval control two commercial formulations, based on diflubenzuron and Bacillus thuringiensis var. israelensis (H-14), have been used. Against adults a deltamethrin based product has been sprayed on the walls and roofs of animal shelters. Adult Culicoides have been collected on each farm twice a week with an Onderstepoort blacklight suction trap. After each treatment a significant reduction in the abundance of total Culicoides, C. imicola and C. newsteadi s.l., has been observed. The Obsoletus complex density has been affected by the first two treatments. Our results suggest the possibility to control the Culicoides populations with a combination of adulticide and larvicide treatments.

Selectivity of different biological products to the egg parasitoid Telenomus remus (Hymenoptera: Platygastridae)

The selectivity of five entomopathogens and a chemical insecticide (positive control) to pupae and adults of the egg parasitoid Telenomus remus (Nixon) was evaluated in the laboratory under controlled environmental conditions according to protocols established by the International Organization for Biological Control. Baculovirus anticarsia (Baculovirus AEE®), Bacillus thuringiensis var. kurstaki (Thuricide®), Bacillus thuringiensis var. aizawai (Agree®), Beauveria bassiana (Boveril®), Metarhizium anisopliae (Metarril®) and Trichoderma harzianum (Trichodermil®) are harmless to T. remus pupae, and adults. Thus, our results suggest that the insect control strategies applied here are compatible since entomopathogens were classified as harmless to T. remus in most examined cases and therefore facilitate a joint application to control different pests. Bacillus thuringiensis var. kurstaki (Dipel®), despite being classified as slightly harmful in some of the evaluations, can still be considered compatible for use together with T. remus, especially when compared with chemical insecticides such as chlorpyrifos that might be considered harmful to the parasitoid survival.

Control del mosco fungoso negro, Lycoriella ingenua (Dufour, 1839) y Bradysia impatiens (Johannsen, 1912) (Dipteria: Sciaridae) en Pinus montezumae Lamb.


 
 
 Los moscos fungosos negros, Lycoriella ingenua y Bradysia impatiens son insectos que afectan significativamente la producción de plántulas de Pinus montezumae en algunos viveros e invernaderos forestales que se ubican en el centro de México. En los meses desde la primavera hasta el otoño, las condiciones ambientales de alta humedad y temperatura son adecuadas para que la población aumente rápidamente y sea abundante en pocas semanas. Para ofrecer una alternativa de control de ellos, en el vivero forestal de Temamatla se probaron cinco insecticidas químicos: oxamil, espirotetramat, imidacloprid, carbofuran, clorpirifos, y el bioplaguicida Bacillus thuringiensis var. israelensis (BTI). Estos productos se aplicaron en tres dosis, durante cuatro meses. La eficacia de los tratamientos se evaluó en porcentaje de plantas sin daño. De los tratamientos, el imidacloprid en dosis alta y media generó una protección de 100 %. Después, oxamil y espirotetramat en dosis alta, a 96.17 % y 95.75 % de la planta tratada. En cambio, la dosis media de clorpirifos lo hizo a 95.74 %, mientras que la dosis baja de imidacloprid, a 95.29 %. Ocho tratamientos protegieron de 91.5 % a 79.43 %, pero cuatro tratamientos no fueron diferentes al control. Los resultados sugieren que no todos los productos evaluados, en sus diferentes dosis, son efectivos para el control del mosco fungoso negro. Sin embargo, algunos pueden serlo para controlarlo en plántulas de P. montezumae.