Resumo em Inglês:

ABSTRACT The obstacles in Phakopsora pachyrhizi management result especially from susceptible soybean genotypes and resistant fungal strains. The objective of the current study was to evaluate the applicability of the emission of extremely low and specific frequencies by Effatha technology in the soybean Asian rust control, nutrition, and its impact on yield. The in-vivo test followed the detached leaves method, with six treatments: frequencies 1 and 2 individually and in association; the conventional chemical treatment (fungicide azoxystrobin + benzovindiflupyr); and witnesses in presence and absence of the fungus. Frequency 1 relates to inhibition of the enzyme succinate dehydrogenase and 2 to ubiquinone oxidase. In the field, frequencies 1 and 2 associated (with the same fungicidal action of the in-vivo study); nutritional frequency; application of azoxystrobin + benzovindiflupyr + mancozeb, and control without application were evaluated. In vivo, the fungicide provided 85% control of the disease symptoms, against 65% of frequencies 1 and 2 in association, which showed a higher efficiency compared to the isolated frequencies. In the field, the rate of increase of symptoms were reduced by all treatments compared to the control. At the end of the soybean cycle, the conventional fungicide resulted in 33% severity against 56% of frequencies 1 and 2 associated, and 69.2% of the control. The emission of the frequency for increased nutrient efficiency stood out positively on yield in relation to all the other ones. The conventional application provided the highest weight of 1,000 grains, possibly a direct reflection of the better control of the disease.

Resumo em Inglês:

ABSTRACT White mold, caused by the fungus Sclerotinia sclerotiorum, is a disease of agronomic importance that affects crops such as soybeans and beans. Considered an aggressive pathogen, it causes symptoms in different parts of the plant, and its control is difficult due to the formation of resistance structures called sclerotia, which allow it to survive in the soil for long periods. The objective of the present study was to evaluate the effectiveness of different concentrations of pyroligneous extract (PE) from sugar cane in suppressing the carpogenic germination of S. sclerotiorum in vitro. The concentrations tested were 0; 1,000; 2,000; 3,000; 4,000 and 5,000 ppm. The extract was incorporated into water agar medium and poured into gerbox boxes with 20 sclerotia. The total number of sclerotia with emission of stipes and apothecia, the total number of sclerotia with emission of stipes and the total number of sclerotia with apothecia were quantified. There was a significant difference in carpogenic germination between the treatments evaluated. Increasing concentrations of sugarcane PE negatively affected the carpogenic germination of sclerotia, the number of stipes per sclerotium and the number of apothecia formed per sclerotium. It was found that sugarcane PE did not inhibit the formation of stipes, but made it difficult to differentiate them into apothecium, especially at the concentration of 5,000 ppm. Sugarcane PE at concentrations of 4,000 and 5,000 ppm promoted reduction in the percentage of germinated sclerotia, as well as in the number of apothecia per sclerotium.

Resumo em Inglês:

ABSTRACT Aiming to the red mite Oligonychus yothersi control in yerba-mate, the systemic action of an azadirachtin-based product (12 g of azadirachtin.L-1) was evaluated in the laboratory. To assess the activity on oviposition and mortality of the mite (1), three weekly applications of the product in an aqueous solution (30, 48, and 66 mg i.a..L-1) were performed. The applications were carried out in the soil, next to the base of yerba mate seedlings. After seven days of each application, leaves were removed for infestation with 15 adult mite females. To evaluate the activity in the development, survival, and reproduction of the progeny (2), yerba mate seedlings were irrigated with azadirachtin solution of 30 mg i.a..L-1 (recommended concentration). After seven days, leaves were removed and infested with adult females for oviposition and observation of the progeny. Reduction in fecundity (from 23.7 to 44.2%), fertility (27.4 to 48.1%), and an increase in mortality from 14.6 to 47.5% were observed in females fed on azadirachtin-treated plants. Continuous feeding on plants treated with azadirachtin solution significantly reduced oviposition, pre-oviposition period, and longevity of males. In addition, the viability of the egg-adult, and the duration of the egg-adult period increased. The potential of azadirachtin for the control of O. yothersi and its action from the irrigation of yerba mate plants was confirmed.

Resumo em Inglês:

ABSTRACT Among the management and control tactics of the coffee berry borer Hypothenemus hampei (Ferrari), there is the use of entomopathogenic fungi. Due to the importance of prospecting isolates of entomopathogenic fungi for the control of the coffee berry borer, the objective of this study was to evaluate the efficiency of 26 isolates of entomopathogenic fungi in the control of this insect pest in the laboratory. The coffee berry borers were immersed in a solution adjusted to the concentration of 1 to 3 × 108 conidia/mL of each isolate and the control treatment (sterilized water). After seven days total mortality and confirmed mortality were evaluated. The isolates that caused the highest mortality and two commercial isolates were selected for evaluation of lethal concentration (LC50 and LC90) and lethal time (LT50 and LT90). Coffee berry borers were treated at different conidia concentrations for lethal concentration to assess total and confirmed mortality. For a lethal time, the coffee berry borers were treated at the concentration of 108 conidia/mL of the selected isolates, and, after two days and every 24 hours until the eighth day, the number of dead individuals was verified. Among the 26 isolates evaluated, 24 presented mortality higher than the control treatment, and three presented mortality higher than 85%. In the LC50 and LC90 assays, the IBCB 353 and IBCB 364 isolates were more lethal to H. hampei. In the LT50 and LT90 assays, the IBCB 66 and IBCB 353 isolates caused lethality in a shorter time.

Resumo em Inglês:

ABSTRACT The black aphid Aphis craccivora (Koch, 1854) stands out between the bugs considered cowpea pests. The objective of this study was to evaluate the effects of silicon application on the resistance induction of cowpea plants to the black aphid A. craccivora. The experiment was conducted in the Entomology Laboratory of the Phytosanitary sector of the Centro de Ciências Agrárias at the Universidade Federal do Piauí. The effects of the application of silicon on biological aspects were evaluated using a completely randomized design, with four treatments and 40 repetitions, being: silicon in soil (T1), silicon in soil + leaf (T2), silicone leaf (T3), and control (T4). The following biological variables were evaluated: generation period, reproductive period, fecundity, and daily average of nymphs per female. The silicon and lignin contents were also evaluated in the plants. The silicic acid was applied in a 1% solution around the stem of the plants (soil), 15 days after emergence, by diluting 2 g of the product in 200 mL of water. However, the leaf application was carried out with sprayer five days after application in soil. The non-preference of A. craccivora on bean was also evaluated. The evaluations were performed after 24, 48 and 72 hours of infestation by counting nymphs at 24, 48 and 72 hours and adults at each leaf session. The application of silicon promotes the reduction of the production of nymphs, interfering in the biological aspects of A. craccivora, and has potential to be used in a cowpea pest management program in cowpea.

Resumo em Inglês:

ABSTRACT Root-knot nematodes (Meloidogyne spp.) can cause a reduction up to 50% in the production of sugarcane (Saccharum spp.). Genetic resistance is considered an important component in the management of nematodes. Therefore, the aim of this study was to evaluate the susceptibility of 12 sugarcane genotypes when subjected to parasitism by Meloidogyne javanica and Meloidogyne incognita under controlled conditions in a plant growth chamber. Four experiments were carried out in randomized blocks with 12 treatments and four replicates for M. javanica and three replicates for M. incognita. The treatments were the sugarcane genotypes: RB966928 (susceptibility pattern), RB026842, RB036168, RB036145, RB036065, RB966229, RB036066, RB036068, RB046209, RB036163, RB036153, and RB036059. Each repetition consisted of a 2-L pot with previously autoclaved substrate (1:1 of sand and soil), and a pre-sprouted seedling was transplanted. From pure populations of M. javanica and M. incognita, approximately 2,000 eggs and eventual J2 were inoculated per pot. After 120 days, the final population of nematodes in the root and soil was counted using an optical light microscope and Peters slide, and the reproduction factor (RF) was calculated. Plants that presented RF < 1 were considered resistant, and plants that presented RF > 1 were considered susceptible. Among the 12 genotypes evaluated, 66% were susceptible to parasitism by M. javanica. The genotypes RB046209, RB036163, RB036153, and RB036059 were classified as resistant to M. javanica parasitism. For the species M. incognita, the susceptible genotypes represented 75% of the total, and the resistant genotypes were RB036163, RB036153, and RB036059.

Resumo em Inglês:

ABSTRACT The state of Bahia has the third largest equine herd in Brazil, with the horse industry overtaking several sectors of the economy currently. However, animals may be exposed to several pathogenic agents, especially the equine infectious anemia (EIA) virus. EIA is a persistent viral disease with a worldwide distribution and is considered the main infectious disease in horses. Therefore, this study sought data from serological survey EIA in Itapé and Barro Preto municipalities, inserted in the southern Coastal Identity Territory of Bahia, by using the agar gel immunodiffusion test. A total of 1,880 blood serum samples from Equidae older than 6 months were analyzed from 172 properties. The general prevalence of outbreaks was 25.58% (44/172), presenting 40.47% (34/84) in Barro Preto (cocoa zone) and 11.36% (10/88) in Itapé (livestock zone). The prevalence of positive animals in Itapé was 1.01% and in Barro Preto 12.15%. Each assessed property received a questionnaire with emphasis on sanitary management and a booklet containing basic disease information. It was concluded the EIA is endemic in two epidemiologically distinct areas in the Southern Coastal Identity Territory of Bahia, one with a high prevalence in the cocoa zone for both animals and properties, and the other, in livestock zone, with a significantly low prevalence for animals, however also high for properties. Regarding the risk factors, there was a correlation between the species and age of the animals. Mules and the elderly showed a significant association, probably due to the habitat they live in and longer exposure to the virus.

Resumo em Inglês:

ABSTRACT Leptospirosis is an important zoonosis. The World Health Organization recommends the use of microscopic soroagglutination in the diagnosis of the disease. However, this is a time-consuming technique that offers a risk of contamination to the performer and requires a trained professional. The indirect enzyme-linked immunosorbent assay (ELISA) test presents less risk, is faster, and has lower cost benefit for high sampling. In view of the advantages of using the test, and the importance of the development of techniques that facilitate and make the diagnosis more efficient, the objective of this study was to standardize an indirect ELISA technique using an immunogenic protein of Leptospira spp. for the diagnosis of canine leptospirosis. The standardized test obtained a cut off of 0.314, 76% of sensitivity, 34% of specificity, 53.52% of positive predictive value, 58.62 of negative predictive value, and 55% of accuracy. The protein extraction technique was efficient for antigen production, and the standardized test can be used in the diagnosis of canine leptospirosis.

Resumo em Inglês:

ABSTRACT The importance of in-vitro tests using larvae and adults of the tick Rhipicephalus (Boophilus) microplus in investigating new inputs for its biological control serves as a basis for continuation of field experiments. This article presents in-vitro efficacy data on the fungus Purpureocillium lilacinum (IBCB 130) tested using larvae and engorged females of the tick R. microplus according to modified techniques of SHAW (1966) and MONTEIRO (2014). The efficacy results from the tests on engorged females ranged from 99.6 at the highest concentration used (2x109 conidia/mL) to 51% at the lowest concentration (1x107 conidia/mL). The 50, 90 and 99% lethal concentrations found in the tests on larvae were, respectively, 5.1x108, 5.2x109, and 3.3x1011 conidia/mL. The results from this investigation have enabled field experiments to control the tick R. microplus using the IBCB 130 isolate of the fungus P. lilacinum.

Resumo em Inglês:

ABSTRACT Aphis gossypii Glover (Hemiptera: Aphididae), also known as the cotton aphid, is a notable pest of several crops. Its damage can be direct and indirect. The direct damage is due to its feeding, which causes leaf shriveling, deformation of shoots, and loss of plant vigor. The pest’s indirect damage is through virus transmission to cotton. In Brazil, A. gossypii is considered as a pest to several crops, but there are no references to infestations of this aphid in soybeans. The objectives of this manuscript were to report the presence of A. gossypii infesting and colonizing soybean crops in São Paulo state, Brazil, and to alert the scientific community and farmers about this possible new pest in Brazilian soybean fields.

Resumo em Inglês:

ABSTRACT Lasioderma serricorne (Coleoptera: Anobiidae) is an important pest in the food and tobacco industry in many regions of the world. A species of polyphagic behavior, despite being a pest capable of successfully breeding and developing in a complex variety of products based on grains, spices and animal by-products, there are few occurrences of this species in the northern region of Brazil. This study was carried out to report the occurrence of L. serricorne in rice grains in the city of Rio Branco, in the state of Acre. In June 2020, the presence of developing L. serricorne was observed in rice grain mass. Identification was performed at the species level using available dichotomous keys. As it is the first record of L. serricorne in rice grains in the city of Rio Branco, the monitoring of insects in the mass of rice grains is necessary for investigation in the search for methods for the management of stored grain pests.