查看更多>>摘要：? 2022 Elsevier LtdBecause of the economic importance of fruit flies throughout the world, increased knowledge of alternative hosts of these pests is essential for integrated pest management in economically valuable fruit crops grown in regions where other host plant species such as coffee are also commonly cultivated. Therefore, the objective of this study was to evaluate the suitability of the cultivated coffee species Coffea arabica L. and Coffea canephora Pierre ex A. Froehner as hosts of fruit fly species in the state of Espírito Santo, Brazil, where both coffee species are widely grown in close proximity to a variety of economically valuable, and fruit fly susceptible, commercial fruit crops. Mature fruits of both coffee species were collected from 681 farms in 54 municipalities of Espírito Santo to identify the fruit fly species infesting coffee fruits and determine fruit fly infestation levels. Field and laboratory experiments were also conducted to study the relationships between coffee species and fruit fly infestation and development. Field infestation of coffee fruits by fruit flies was higher in C. arabica than in C. canephora (‘Conilon’). A total of 136.7 fruit fly pupae per kg of C. arabica fruits were found, in comparison to 5.4 pupae per kg of C. canephora fruits, and 97.1% of the adult fruit flies reared from coffee fruits emerged from C. arabica fruits. Ceratitis capitata (Wied.) and Anastrepha fraterculus (Wied.) were the most common fruit fly species associated with fruits of both coffee species. The quantity of C. capitata reared from C. arabica fruits (55.2 adults kg?1) was 15.3 times higher than the quantity reared from C. canephora fruits. Coffea arabica was also a much better host for A. fraterculus than C. canephora based on the number of adults reared from fruits. Results of this study indicate that C. arabica is a potential reservoir host of fruit flies, and therefore may play a significant role in fruit fly pest survival when preferred host fruits are lacking in winter months. This is the first study that compares the two major cultivated coffee species as potential hosts and sources of fruit flies, and indicates that integrated pest management (IPM) should be utilized to inhibit dispersal of fruit flies from C. arabica to nearby areas where commercial fruit crops are grown.
查看更多>>摘要：? 2022 Elsevier LtdFusarium wilt, Phytophthora root rot, and Anthracnose crown rot of strawberry are three infectious diseases that cause growth retardation and even death in strawberry plants. Because these diseases seriously harm the commercial strawberry industry, it is critically important to quickly detect the three causal pathogens. In this study, we established a multiplex PCR (mPCR) system to detect the three strawberry pathogens Fusarium oxysporum f. sp. fragariae (Fof), Phytophthora nicotianae (Pn), and Colletotrichum gloeosporioides (Cg). We identified three primer pairs for specifically detecting these pathogens. This was followed by determining the ideal concentration of each primer pair for mPCR. The optimum annealing temperature was found to be 59.2 °C and the optimal number of cycles was 35. The minimum detection limit of mPCR was 1 ng/μL, which was lower than the single detection sensitivity for each pathogen. Strawberry field samples were randomly selected and 34 diseased plants were assayed using the mPCR system. In the actual application test, our established mPCR can detect pathogens more quickly than conventional culture method. In conclusion, the mPCR system established in this study provides a rapid and effective method for the simultaneous detection of three important strawberry pathogens.
查看更多>>摘要：? 2022 Elsevier LtdRed clover (Trifolium pratense L.) is an important leguminous forage crop of temperate regions throughout the world including India. Red clover suffers serious seed yield losses due to crown rot (caused by Sclerotinia trifoliorum) and powdery mildew (caused by Erysiphe trifoliorum) diseases. Resistant varieties against these two devastating diseases are not available, which necessitates the development of alternate management strategies for these diseases. In order to develop alternate management strategies for these diseases, this study was conducted during 2013–14 to 2017–18 at Palampur (India). Three fungicides (carbendazim, wettable sulphur, hexaconazole) and one biocontrol agent (Trichoderma viride) were tested in different combinations for combined management of these diseases. Results from five year study indicates that seed treatment with carbendazim followed by three foliar sprays of hexaconazole and seed treatment with carbendazim followed by one foliar spray each of T. viride, wettable sulphur and hexaconazole at 10 days interval can effectively control powdery mildew and crown rot diseases, respectively. Applications of these treatments showed significant superiority over others by not only reducing disease severity but also resulted in higher seed yield. Thus, these management strategies can be effectively deployed for simultaneous management of two most serious diseases in red clover.
查看更多>>摘要：? 2022 Elsevier LtdOkra yellow vein mosaic (OYVMD) and enation leaf curl diseases (OELCuD) caused by whitefly (Bemisia tabaci) transmitted begomoviruses are important constraint for improvement and production okra in India. Okra germplasms consists of 178 cultivated/advanced lines (147 Advances okra lines + 31 popular varieties) and 146 accessions from 14 wild species originally collected from different national institutes located at different agro-climatic zones of India were evaluated for their response against OYVMD and OELCuD. The resistance levels both cultivated and wild species were assessed by visual scoring of symptoms in the field under natural conditions for two consecutive years in 2015 and 2016. None of the cultivated genotypes and wild species tested was found to be disease free except Abelmoschus enbeepeegeearnse, however, considerable variation in responses against OYVMD and OELCuD was observed among the genotypes. Of the 178 cultivated/advanced lines screened against OYVMD and OELCuD, seven genotypes showed highly resistant, one resistant, 2 moderately resistant and 146 accessions from 14 wild species, 17 accessions were showed highly resistant reaction, one accession resistant, 5 accessions moderately resistant for OYVMD. Similarly, for OELCuD, fifty-two okra genotypes showed highly resistant, three moderately resistant in cultivated/advanced lines and 125 accessions were found to be highly resistant, two resistant and three moderately resistant in wild accessions. The resistance cultivated/advanced lines could be used directly as varieties to manage OYVMD and OELCuD after adaption to various agro-climatic regions. The resistance in wild accessions could be used in future breeding programmes to develop okra cultivars resistant against both OYVMD and OELCuD.
查看更多>>摘要：? 2022 Elsevier LtdThe brown planthopper, Nilaparvata lugens (St?l), is a major rice pest in Asia. Acetamiprid is a widely used neonicotinoid insecticide for N. lugens control. Because of the frequent and excessive applications of chemical insecticides, moderate levels of resistance against acetamiprid have been found in field populations of N. lugens in China. To study the inheritance mode and fitness costs of acetamiprid resistance in N. lugens, an acetamiprid-resistant strain (AC-R) was selected from a susceptible strain (AC-S) in the laboratory. After 28 generations of selection, AC-R showed 26.15-fold resistance compared to AC-S. The LC50 and degree of dominance (D) values of the F1RS and F1SR (progenies of reciprocal crosses) indicated that the acetamiprid resistance in N. lugens was inherited as autosomal and incompletely dominant. Significant differences between the expected and observed mortalities of the F2 individuals suggested that acetamiprid resistance is controlled by multiple genes. The AC-R strain showed a relative fitness of 0.71 with a significantly decreased male adult longevity, fecundity, net reproductive rate (R0), and finite rate of increase (λ), and a prolonged adult preoviposition period (APOP). However, the durations of the 1st, 2nd, and 4th instar nymphs of AC-R were significantly shorter than those of AC-S. The current study provides valuable information for understanding acetamiprid resistance and optimizing insecticide resistance management strategies of N. lugens in the field.
查看更多>>摘要：? 2022 Elsevier LtdRice production is facing serious threats due to frequent outbreak of brown plant hopper, Nilaparvata lugens (St?l.) population. Globally, four biotypes of N. lugens has been recorded, of which biotype-4 is the utmost damaging one prevailing in Asian subcontinents particularly in India. Therefore, effective management of N. lugens requires durable resistant rice variety with multiple resistant traits and genes. Hence, in the present study 268 rice genotypes were screened against N. lugens. From initial screening results, 96 genotypes were selected for further genotyping using 93 molecular markers linked to 26 different N. lugens resistant (R) genes. Genetic analysis revealed the mean genetic diversity of 0.275 and polymorphic information content of 0.240 for all 93 markers. Genetic association through cluster and population structure analysis clearly differentiated the 96 genotypes into three major genetic groups with resistant genotypes grouped in a separate cluster. Likewise, Principal co-ordinate analysis supported the above claim with susceptible, moderately resistant and resistant genotypes accommodated in separate components. Further, genetic variation among population showed a 92% variation among individuals of the population and only 8% between populations. Marker trait association via generalized linear model (GLM) and multi linear model (MLM) picked out five markers for their significant association with different phenotypic parameters such as percent damage, nymphal survival, feeding mark and honeydew excretion. Three markers viz. RM19291 (Bph30), RM28472 (Bph18) and RM28449 (Bph17) were common for both GLM and MLM analysis. These identified resistant genes in rice landrace will serves as the source for development of durable resistant variety against N. lugens.
查看更多>>摘要：? 2022 Elsevier LtdIn order to identify new sources of resistance to leaf rust, a globally important disease of wheat, caused by the fungal pathogen Puccinia triticina Eriks. (Pt), a total of 170 hexaploid breeding lines, which have similar morphology with wheat and were derived from crosses of wheat-Thinopyrum ponticum or wheat-Th. intermedium partial amphiploids with susceptible wheat cultivars, were inoculated with the selected Chinese Pt races for evaluating seedling leaf rust response in the greenhouse. The response of adult plants to leaf rust was assessed on seedling susceptible lines over three cropping seasons from 2017 to 2020. In addition, 24 specific markers for 20 known Lr genes were used. Based on the results from gene postulation and molecular marker detection, two adult plant resistance (APR) genes (Lr34 and Lr37) and nine seedling resistance genes (Lr1, Lr2a, Lr2b, Lr3ka, Lr10, Lr15, Lr17, Lr18, and Lr26) were identified in 118 lines either singly or in combination. Most commonly identified Lr genes were Lr37 in 81 (47.6%) lines and Lr26 in 40 (23.5%) lines. Less frequently detected genes were Lr1 in nine lines; Lr2b and Lr3ka each in eight lines; Lr17 in seven lines; Lr2a and Lr34 each in four lines; Lr10 in three lines; Lr18 in two lines; and Lr15 was found in only one line. Twenty-eight lines were resistant to almost all the races used, but no known resistance gene was identified except Lr26, a gene with widespread ineffectiveness, suggesting that these derivatives could possess uncharacterized seedling Lr gene(s). Eleven seedling-susceptible lines were found to have APR over three cropping seasons, with an average maximum disease severity (MDS) below 15%, and hence could be potential sources of new APR genes. This study showed that these hexaploid breeding lines derived from wheat-Thinopyrum amphiploids could serve as new sources for wheat leaf rust resistance.
查看更多>>摘要：? 2022 National Agricultural Research OrganizationStem borers are major insect pests of maize in Uganda. A study was conducted in 2014–2016 to assess the performance of Bt hybrids expressing Cry1Ab (event MON810) against the two major stem borer species in Uganda – the African stem borer (Busseola fusca) and the spotted stem borer (Chilo partellus) – under artificial infestation. The study comprised 14 non-commercialized hybrids, including seven pairs of Bt and non-Bt hybrids (isolines), three non-Bt commercial hybrids and a conventional stem borer resistant check. All stem borer damage parameters (leaf damage, number of internodes tunneled and tunnel length) were generally significantly lower in Bt hybrids than in their isolines, the conventionally resistant hybrid, and local commercial hybrids. Mean yields were significantly higher by 29.4–80.5% in the Bt hybrids than in the other three categories of non-Bt hybrids. This study demonstrated that Bt maize expressing Cry1Ab protects against leaf damage and can limit entry of stem borers into the stems of maize plants, resulting in higher yield than in the non-transgenic hybrids. Thus, Bt maize has potential to contribute to the overall management package of stem borers in Uganda.
查看更多>>摘要：? 2022The authors regret that the printed version of the above article contained a number of errors. The correct and final version follows. The authors would like to apologise for any inconvenience caused.
查看更多>>摘要：? 2022 Elsevier LtdSpring dead spot (SDS) (Ophiosphaerella spp.) causes damage to hybrid bermudagrass (Cynodon dactylon (L.) Pers. x transvaalensis Burtt Davy) grown in areas where winter dormancy occurs. The pathogen infects the stolons, rhizomes, and roots of warm-season grasses. Symptoms appear as circular, necrotic patches at spring greenup that reduce the playability and aesthetics of bermudagrass. Historically, fungicide efficacy against SDS has been inconsistent. There may be opportunities to improve application and post-application practices to mitigate the inconsistency. A study was conducted from 2019 to 2021 to examine the influence of post-application irrigation and soil surfactant on tebuconazole efficacy against SDS. The study was conducted at three locations: Virginia Tech Turfgrass Research Center (TRC), Blacksburg, VA; Independence Golf Club (IGC), Midlothian, VA; Nutters Crossing Golf Club (NCGC), Salisbury, MD. Tebuconazole was applied in the fall either once at 1.5 kg ai ha?1 or twice at 1.5 kg ai ha?1 two to four weeks apart when soil temperatures were between 10.7 and 21.8 °C. Treatments were applied with or without a soil surfactant and with or without 0.6 cm of post-application irrigation. Bermudagrass was assessed the following spring two or three times for patch number and percent SDS. Data were analyzed by assessment date, subjected to analysis of variance, and means were separated using Tukey's Honest Significant Difference test (P = 0.05). There were no treatment differences at IGC or NCGC in 2020 or 2021. At the TRC in both 2020 and 2021, results were inconsistent with tebuconazole generally suppressing SDS compared to the nontreated control. However, differences between tebuconazole-treated plots were variable. Our study suggests that including a soil surfactant with tebuconazole applications and/or irrigating post-application does not consistently increase SDS suppression.
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