查看更多>>摘要：? 2021 Elsevier LtdSclerotinia sclerotiorum (Lib.) de Bary causes white mold on lima bean (Phaseolus lunatus), resulting in significant yield and quality loss. Fungicides are widely used to manage white mold, yet there are no application-timing guidelines for lima bean. The knowledge gap impedes research for effective fungicide efficacy and for integrated management that combines fungicides with biological and cultural practices. Trials to determine the optimum timing for fungicide application were conducted from 2014 to 2017 with Endura 70WG (0.76 kg ha?1; a.i. boscalid) at four locations in the mid-Atlantic region. Fungicides were applied (i) at approximately 20% bloom initiation when at least 20% of plants had opened flowers; (ii) approximately one week later at 100% bloom initiation when 100% of plants had opened flowers; (iii) approximately one week later when plants were in full bloom; (iv) approximately one week later when pods were developing; (v) a double application at 20% and 100% bloom initiation; and (vi) non-sprayed [non-treated control (NTC)]. White mold incidence as number of infected plants m?1 of row, white mold severity as percentage of infected tillers per plant m?1 of row and yield (kg) from 2.3 m2 subsection of row area were recorded. Double applications at 20% and 100% bloom initiation resulted in the greatest reduction in white mold incidence and severity in most environments. However, the Endura applications one and two weeks after 100% bloom initiation reduced disease incidence by 50% and 54% in 2016 and white mold severity between 63% and 79% in 2015 and 2016. This research will provide a foundation for the development of fungicide application guidelines, and for research on use of fungicides in integrated white mold management programs for lima bean.
Martins Soares P.L.Braz L.T.Gomes-Messias L.M.Macedo da Silva E....
7页
查看更多>>摘要：? 2022 Elsevier LtdRoot-knot nematodes (Meloidogyne spp.) are one of the major pests of agricultural crops worldwide. In Brazil, these nematodes are widely distributed in melon fields, and there are no reports of resistant melon cultivars. This study aimed to estimate genetic variance components for the selection of melon genotypes resistant to Meloidogyne incognita, M. javanica, and M. enterolobii. Two experiments were carried out in a completely randomized design, the first with 14 replications and the second with 10 replications, in a factorial design. Thirteen melon genotypes were tested. In both experiments, the total number of eggs and juveniles (TNEJ) was estimated and used to determine the reproduction factor (RF) and reproduction index (RI) of nematodes. Melon genotypes showed wide genetic variability in resistance to the three nematode species, resulting in high estimates of heritability (92%) and accuracy (96%). Such findings indicate the possibility of genetic gains with selection. Melon AC-09, PI157082, and ‘Ouro’ were found to be sources of resistance to M. incognita, M. javanica, and M. enterolobii, respectively.
查看更多>>摘要：? 2022Despite intensive control efforts, whitefly Bemisia tabaci, remains a difficult pest to manage due to its wide host range and ability to easily switch feeding between crop hosts and surrounding weed hosts. To develop more economical management strategies, the combination of kaolin and limonene was tested as a natural organic repellent against whiteflies. Whitefly host selection was compared between kaolin and limonene-coated tomato and control plants using closed cage bioassays. Combining limonene and kaolin had an additive effect on repelling adult whiteflies compared with the control. Field trials were conducted during two fall seasons in Quincy, Florida. In the 2019 field trial, during dry conditions, tomatoes treated with kaolin + limonene (K + L) had a three to four-fold reduction in B. tabaci adult populations compared to controls and a two to three-fold reduction compared to kaolin-only and limonene-only treatments. In addition, infection with Tomato Yellow Leaf Curl Virus (TYLCV) was at least two times lower on average in K + L treatments compared to the control. This translated to a two-fold increase in marketable yield of tomatoes harvested from K + L treatments. In fall 2020, due to wetter conditions we only observed a decrease in adult populations on plants in the K + L treatment compared to the control, yet no difference in TYLCV incidence between treatments. Limonene-scented kaolin's effectiveness as a whitefly repellent seems to depend largely on rainfall. In dry conditions, more effective control of whiteflies and of TYLCV was achieved.
查看更多>>摘要：? 2021 Elsevier LtdThe fall armyworm, Spodoptera frugiperda (J. E. Smith, 1797) emerged as a major threat to several maize growing countries worldwide. To manage this pest outbreak, farmers rely heavily on insecticides. Seed treatment with insecticides in maize is often the most pragmatic fall armyworm (FAW) management tactic. The aim of this work was to determine the bioefficacy, persistent toxicity, and persistence of translocated residues of insecticide seed treatments in maize used for the management of FAW. Bioefficacy of several seed treatment insecticides (Thiamethoxam, fipronil, tetraniliprole, chlorantraniliprole, cyantraniliprole + thiamethoxam, tetraniliprole + fipronil) was evaluated via foliar damage rating after crop emergence using the Tamil Nadu Agricultural University damage scoring scale. Persistent toxicity was assessed through a laboratory bioassay using the first instar larvae that fed on seed-treated maize leaves. Persistence of translocated residues was studied using Liquid Chromatography-Mass Spectrometry/Mass Spectrometry technique. Chlorantraniliprole 62.5 FS @ 6 ml kg?1 seed provided the highest protection followed by cyantraniliprole + thiamethoxam 19.8 FS, tetraniliprole 480 FS, and tetraniliprole + fipronil 240 FS. An increase in damage rating was observed 10 and 12 days post crop emergence. at 10 and 12 days post crop emergence with treatments involving diamides, except for chlorantraniliprole. Thiamethoxam and fipronil seed treatments were ineffective in FAW larvae management. Chlorantraniliprole residues persisted for >26 days, and cyantraniliprole + thiamethoxam residues persisted for >16 days in maize seedlings. The field bioefficacy of diamide insecticides residues matched with their toxicity persistence in laboratory bioassays, revealing them as best fit seed treatments when compared with thiamethoxam and fipronil. Seed treatment in maize with these diamide insecticides will be useful up to 15 days post crop emergence in preventing FAW foliar damage.
查看更多>>摘要：? 2021 Elsevier LtdFreshwaters and particularly small water bodies are constantly threatened by the use of pesticides in agriculture. These risks have to be mitigated and reduced according to the European Sustainable Use Directive. The creation of vegetated buffer strips is one measure to effectively mitigate the pesticide risk to freshwaters in agricultural landscapes. This study quantifies the buffer strip effects on pesticide risk posed by arable crop farming for German freshwaters using the pesticide risk indicator model SYNOPS. A constant but only slight turnover towards pesticides with lower water body distance requirements over time was observed when no buffer strips were present. However, the presence of buffer strips contributed to a much higher extent to pesticide risk reduction to freshwaters. The chronic risk to freshwaters was reduced by 29% (simulating 5 m buffer strips) and by 47% (simulating 10 m buffer strips). The effect of risk mitigation by buffer strips varied between crop type and pesticide type. Highest effects of buffer strips were achieved for herbicides and in oilseed rape. Overall, the results show that the creation of buffer strips is a crucial step to effectively mitigate pesticide risk to freshwaters in agricultural landscapes.
查看更多>>摘要：? 2021 Elsevier LtdWatermelon (Citrullus lanatus var. lanatus) yield losses due to Fusarium wilt can be considerable and have been increasing in the United States, mainly due to the emergence of the new races of Fusarium oxysporum f. sp. niveum (FON). One of the potential management strategies to reduce Fusarium wilt is the use of fumigants and soil-applied fungicides. Field experiments were conducted in 2018 and 2020 to evaluate fumigant Pic-clor 60 (choloropicrin pre-mixed with 1,3 dicholoropropene) with post-plant soil-applied fungicides (prothioconazole and pydiflumetofen) for their effectiveness against Fusarium wilt. The field was fumigated 21 days before transplanting, and three applications of either fungicide were made at 14-day intervals via a drip irrigation system starting a day after transplanting. In 2018, based on the disease ratings at harvest maturity, all treatments significantly reduced final disease incidence compared to the non-treated control, and the highest reduction was observed when the fumigant was applied at 336.26 kg/ha along with either fungicides. The application of fumigant, together with either fungicides, had significantly higher reduction in disease incidence compared to the stand-alone application (fumigant or fungicides). Also, Pic-clor 60 at 336.26 kg/ha provided a higher reduction in disease incidence than Pic-clor 60 at 280.21 kg/ha. In 2020, results showed a similar trend to 2018, where Pic-clor 60 at 336.26 kg/ha in combination with either prothioconazole or pydiflumetofen had significantly lower final disease incidence. The reduction in disease incidence in Pic-clor 60 at 336.26 kg/ha was higher compared to a lower application rate of 280.21 kg/ha, either when applied alone or in combination with either fungicides. The results presented here are the first to demonstrate that the fumigant Pic-clor 60 along with soil-applied fungicides, pydiflumetofen or prothioconazole may provide an effective management option for Fusarium wilt of watermelon.
查看更多>>摘要：? 2021Pepper weevil, Anthonomus eugenii Cano is the most harmful insect pest of pepper, Capsicum annum L., an important crop in Florida and several other states in the southern region of the United States. All commercially cultivated peppers, including jalape?o peppers, are susceptible to pepper weevil. The use of broad-spectrum insecticides is the primary management tool for controlling pepper weevil. Their continuous use has led to the development of resistance and elimination of natural enemies. Therefore, alternative approaches are needed for effective control. Studies were conducted to evaluate the effectiveness of intercropping non-host insect repellent plants (Ocimum basilicum L. (basil), Tagetes patula L. (marigold), Brassica oleracea L. (cabbage), and Coriandrum sativum L. (cilantro)) with jalape?o pepper on pepper weevil population suppression. Each of the four non-host plants consisted of individual treatments and were compared to a jalape?o pepper only (untreated control), or a jalape?o pepper with a standard insecticide regimen of thiamethoxam (positive control). Parameters evaluated include the number of pepper weevil adults on plants, number of infested fallen fruit, and marketable yield. Infested fruit collected from each treatment plot were dissected to evaluate pepper weevil (adult, pupae, and larvae) density. The non-host plant treatments reduced the number of pepper weevil adults found on jalape?o plants, infested fruit, and pepper weevils in infested fruit but not marketable yield when compared with the control treatment. This information is a step forward into finding a sustainable approach for the management of pepper weevil.
查看更多>>摘要：? 2022 Elsevier LtdPowdery mildew, caused by Podosphaera aphanis, is an important disease of strawberries under protection. Botrytis fruit rot is an important cause of losses in strawberries particularly under open-field conditions. Current control of both these diseases in the UK is dependent on conventional fungicides. Recently, research in the UK demonstrated that integrating biopesticides and biostimulants with a decision-based management programme could achieve reductions in conventional fungicide use without loss in yield or fruit quality. Further field studies were conducted to extend the decision-based management programme to include control of Botrytis fruit rot on everbearer crops. In 2018, three management programmes were compared to a routine fungicide-based programme and an untreated control. In two management programmes, treatments for Botrytis and powdery mildew were either applied routinely or managed. In the third programme, treatments for both diseases were managed. Disease risks were estimated with a simple lookup table based on past and forecast weather. The results showed that the integrated management for both diseases resulted in a nearly 45% reduction in conventional fungicide use and a cost saving of ￡699/ha compared to a routine programme with no penalties in yield, fruit quality or disease control. There were no significant effects of treatments on Botrytis rot incidence compared to the untreated control, suggesting that the fungicides applied for controlling Botrytis gave no benefit. In 2019, two treatments based on the decision-based management system for powdery mildew and Botrytis, one of which excluded specific fungicide treatment for Botrytis, were compared to an untreated control and a routine fungicide programme. Cool chain management of the fruit post-harvest was also included to extend post-harvest fruit shelf life. The results showed that the simple decision-based system for determining treatments for mildew and Botrytis based on biopesticides and omitting Botrytis-specific fungicides resulted in a 93% reduction in fungicide use and a cost saving of ￡924/ha compared to a routine programme with no penalties in yield, fruit quality or disease control. Cool chain management delayed the development of both Botrytis and soft rots. In both years, detectable fungicide residues were considerably reduced in the fruit from the managed programmes.
De Rossi R.L.Guerra F.A.Plazas M.C.Vuletic E.E....
10页
查看更多>>摘要：? 2022 Elsevier LtdNorthern corn leaf blight (NCLB), caused by Exserohilum turcicum (E. turcicum), is one of the most common maize (Zea mays L.) diseases worldwide. To determine the crop damage and economic losses caused by NCLB and propose economic damage thresholds (EDTs), 16 field experiments were performed for seven crop seasons (2010–11 to 2016–17) during different naturally occurring outbreaks of NCLB in central-northern Córdoba province, Argentina. NCLB severity gradients were generated by applying different fungicides and doses at different growth stages to seven susceptible (S) and nine moderately susceptible (MS) hybrids. Plots were arranged in a completely randomized block design with four replications. Severity was evaluated at the R4 growth stage by estimating the percentage of leaves affected; and grain yield in kg ha?1 per plot was also estimated. A critical-point yield model was fitted with NCLB severity and the EDT and the action damage threshold (ADT) were calculated. The management regime generated disease gradients with severities ranging between 3.2 and 33.1. There was a statistically significant negative correlation between severity and yield (R2 = 0.52; p = 0.001). On average, for each percentage point increase, in NCLB severity, 20.15 kg t?1 of yield were lost; MS and S hybrids were 23.88 kg t?1 and 15.21 kg t?1, respectively. The mean EDT was 1.09% of severity and the mean ADT was 0.88%. Furthermore, the mean economic losses were 243.6 USD ha?1 [122.0–353.2]. The generated information can play a role in optimizing the use of fungicides for NCLB control, reducing disease control costs, and protecting the ecological environment of farmlands.
查看更多>>摘要：? 2021Anthracnose caused by Colletotrichum species is a devastating disease on Brassica parachinensis which affect the crop production and cause economic losses in China. During the period from 2012 through 2018, samples of diseased leaves of B. parachinensis showing anthracnose-like symptoms, that is irregular and slightly sunken lesions in gray to brown color with or without small black spots symptoms were collected in open fields of B. parachinensis from 11 prefecture-level cities of Guangdong province in southern China. One hundred and two isolates of Colletotrichum were obtained from single spore cultures. Based on cultural and morphological characteristics, 86 and 13 isolates were identified as C. higginsianum and C. truncatum, respectively. However, other three isolates were morphologically different from C. higginsianum and C. truncatum, but similar to C. fructicola. To confirm the identification, the internal transcribed spacer (ITS) region, actin (ACT), chitin synthase 1 (CHS1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH) and beta-tubulin (TUB2) genes were amplified. Phylogenetic analysis showed that the ITS, ACT, CHS1, GAPDH and TUB2 sequences of these three isolates clustered with sequences belonging to the ex-type strain ICMP 18581 of C. fructicola with a posterior probability value of 1. Pathogenicity assays showed that all these three isolates could infect healthy leaves, stems and flowers of B. parachinensis and cause typical leaf and stem rot symptoms originally observed and also flower rot symptoms that rarely occurred on B. parachinensis in the fields. The same pathogen was re-isolated from lesions of inoculated plants. Distribution investigation showed that C. higginsianum is widely distributed and is the major pathogen causing anthracnose of B. parachinensis in Guangdong. C. fructicola and C. truncatum distributed across through the north to the south regions and through the east to the west regions of Guangdong, respectively. To our knowledge, this is the first report of C. fructicola as a causal agent of anthracnose on B. parachinensis in China.
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