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A two-year (2012–2013) field experiment was carried out to investigate the fungicidal activity of pyraclostrobin and its putative physiological effects on sunflower ( Helianthus annuus L.) grown under rainfed, Mediterranean conditions. Five pyraclostrobin treatments were applied [single applications at rates of 100, 150 and 200 g active ingredient (ai) ha −1 at V6 growth stage (T V6/100 , T V6/150 , and T V6/200 , respectively) and 200 g ai ha −1 at R1 growth stage (T R1/200 ) and a double application at V6 and R1 at a rate of 100 g ai ha −1 (T V6-R1/100 )] and accompanied by untreated (T UC ) and chemical control [iprodione at a rate of 750 g ai ha −1 at V6 (T CC )]. Diseases [charcoal rot (CR) caused by Macrophomina phaseolina , Phomopsis stem canker (SC) caused by Phomopsis helianthi , black stem (BS) caused by Phoma macdonaldii , and powdery mildew (PM) caused by Golovinomyces cichoracearum ] were assessed twice. Leaf physiological traits [leaf chlorophyll content (SPAD), specific leaf area (SLA), carbon isotope discrimination (Δ), nitrogen (N) concentration, 15 N natural abundance (δ 15 N), and carbon to nitrogen ratio (C/N)] were determined at R5 stage. Growth season had a significant effect on seed oil concentration (Oil) and oil yield (OY) and was higher in 2013; this season had low CR and SC incidence but high incidence of BS and severity of PM. Split application of pyraclostrobin (T V6-R1/100 ) or a high rate at the beginning of the reproductive phase (T R1/200 ) suppressed the diseases, mainly SC and BS. The former treatment (T V6-R1/100 ) showed the highest yields [seed yield (SY), OY, and protein yield (PY)]. All the physiological traits but Δ were not affected by fungicide treatments. The high-yielding T V6-R1/100 treatment had the highest Δ values over the growth seasons indicating a “waste” of water in turn to sustain open stomata and thus higher CO 2 exchange rates. This swap leads to lower water use efficiency in the long-term but it indicates healthier and more active functioning sunflower plants that had greater yields. Phomopsis stem canker (SC) showed to be the most detrimental disease since its incidence was negatively correlated to yields (SY, OY) over the growth seasons. On the other hand, CR seemed to affect N uptake and translocation within sunflower plants. In conclusion, the physiological response (highest Δ) recorded for split application of pyraclostrobin (at V6 and R1 stages) was indirect; lower disease incidence secured water supply to sunflower plants resulting in higher yields. [ABSTRACT FROM AUTHOR]

Fig (Ficus carica L.) is one of the oldest fruits that is extensively cultivated worldwide. It has gained a lot of interest among growers due to its unique characteristics, nutritional values, and medicinal properties. Like other fruit crops, each part of the plant is susceptible to fungal diseases that affect fruit production and its quality. Samplings conducted from September 2018 to March 2019 showed that fig plants have been infected by leaf blight, stem canker, and anthracnose fruit rot. The present study aims to determine the causal pathogens of those diseases using morphological, molecular, and pathogenicity analyses. A total of 28 blighted leaves, 11 cankered stems, and 18 anthracnose-rotted fruits of F. carica were collected from different nurseries in several states in Malaysia. The results of morphological characterization, DNA sequences, and phylogenetic analysis of internal transcribed spacer (ITS), β-tubulin (tub2), and glyceraldehyde-3-phosphate dehydrogenase (gapdh) revealed that, of the 39 fungal isolates obtained, they belong to Colletotrichum fructicola (one isolate), C. siamense (30 isolates), and C. truncatum (eight isolates). From the 30 isolates of C. siamense , 10 isolates were obtained from leaves, eight isolates from stems, and 12 isolates from fruits, whereas eight isolates of C. truncatum , and one isolate of C. fructicola were obtained from leaves. The pathogenicity tests conducted on F. carica confirmed that C. fructicola , C. siamense , and C. truncatum were the causal pathogens of leaf blight, while stem canker and anthracnose fruit rot were caused by C. siamense. The present study highlighted three different Colletotrichum species namely C. fructicola , C. siamense , and C. truncatum associated with diseased figs (F. carica) in Malaysia. [Display omitted] • The occurrence of leaf blight, stem canker, and anthracnose fruit rot of fig (Ficus carica) was observed in Malaysia. • Fungal identification was confirmed by morphological characteristics, DNA sequences, and phylogenetic analysis of ITS, tub2 , and gapdh. • Of thirty-nine fungal isolates, they belong to Colletotrichum fructicola , C. siamense , and C. truncatum. • C. fructicola , C. siamense , and C. truncatum cause leaf blight; stem canker and anthracnose fruit rot caused by C. siamense. [ABSTRACT FROM AUTHOR]

• Spatial characterisation of plantation carbon is critical for species selection. • We spatially predict carbon for Cupressus lusitanica and macrocarpa in New Zealand. • The models highlighted different environmental preferences for the two species. • Mean carbon was higher for C. macrocarpa than C. lusitanica. • Species differences were greatest in the South Island. • Carbon was higher for C. macrocarpa in 62 and 94% of the North and South Islands. Cupressus lusitanica and C. macrocarpa are two fast growing conifer species with valuable timber that have been widely established throughout New Zealand. Despite the importance of these two species within New Zealand and in many other countries, little research has investigated how volume, height, and carbon productivity are influenced by environment. Volume growth of these two cypress spp. has been recently described using the 300 Index which quantifies the mean annual volume increment at age 30 yrs for a stand density of 300 stems ha−1. Using New Zealand growth data obtained from 290 plots, the objectives of this study were to (i) develop models and fine resolution national maps of 300 Index and site index, (ii) use these two productivity metrics and allometric equations to develop models of carbon stocks for the two species, and (iii) spatially predict carbon across New Zealand for C. lusitanica and macrocarpa grown under a factorial range of stand densities (400, 650 and 900 stems ha−1) and ages (30, 40 and 50 yrs). Plot measurements showed wide variation in 300 Index which reached 26.9 and 29.0 m3 ha−1 yr−1, respectively, for C. lusitanica and C. macrocarpa. Site index (age 30 yrs) reached values of 31.9 and 34.1 m for C. lusitanica and C. macrocarpa , respectively. Models developed for C. lusitanica had high accuracy for both 300 Index (RMSE = 2.48 m3 ha−1 yr−1; R 2 = 0.75) and site index (RMSE = 1.78 m; R 2 = 0.84) while models developed for C. macrocarpa had similar, but slightly lower, accuracy for 300 Index (RMSE = 2.86 m3 ha−1 yr−1; R 2 = 0.72) and site index (RMSE = 1.86 m; R 2 = 0.81). Spatial predictions of the two productivity metrics showed distinct differences between species with C. lusitanica being more sensitive to cold, dry, and wet conditions than C. macrocarpa. Under the mid-range scenario (age 40, 650 stems ha−1) mean carbon sequestration in above and below ground biomass, dead wood, and litter pools for C. macrocarpa was higher than C. lusitanica in both the North Island (321 vs. 296 t C ha−1) and South Island (222 vs. 120 t C ha−1). Carbon was higher for C. macrocarpa than C. lusitanica within, respectively, 62 and 94% of the North and South Islands under the mid-range scenario. Carbon markedly increased with stand density and age and gains were greatest between ages 30 and 40 and from the low to moderate stand density for both species. [ABSTRACT FROM AUTHOR]

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Cocoa genotypes, selected locally or obtained from the progeny of hybrid crosses and propagated clonally in two trials in Pinrang and Polman Districts, Sulawesi, were evaluated for resistance to Phytophthora pod rot (Ppr) and stem canker caused by Phytophthora palmivora . In each trial, 10–12 clones, including four common to both sites, were evaluated for infections occurring naturally on the farm or induced by artificial inoculation of stems and attached pods. At each site, incidence and severity of stem canker in the clones were evaluated in the early and late wet season of 2013/2014, while Ppr incidence was determined from the cumulative pod harvest of 2010–2012. Incidence and severity of stem canker in the six-year old trees were highly correlated in both years and were higher in Pinrang than Polman, with marked increases during the wet season occurring in more susceptible genotypes (e.g. 65.6%–90.6% incidence in GeniJ in Pinrang). Although Ppr incidence in all clones increased during wet periods, some clones maintained a lower incidence than others during the two year period of evaluation: for example, between the dry season of 2011 and following wet season average Ppr incidence increased from <5% to 26% in the local clone M06 and <20%–46% in the more susceptible RB. Average lesion size following artificial inoculation was higher in both pods and stems in the Pinrang, than the Polman, trial. Positive correlation between results of artificial pod tests and total field Ppr incidence (including immature and ripe pods) suggest that artificial inoculation of attached pods is a reliable method to evaluate Ppr resistance. Similarly, lesion size in different clones following artificial inoculation of stems was positively correlated with naturally occurring stem canker severity. Inconsistencies between responses to inoculated and naturally occurring P . palmivora were found in some clones, for example, ICCRI04, selected from progeny of a hybrid cross with Sca12, and Geni J, a local farm selection, indicating the importance of confirming artificial resistance tests with evaluations on the farm. While resistance to both diseases was confirmed in some local selections notably M06, M05 and Panimbu Red, no significant correlation occurred in either trial in the responses to stem canker and Ppr (whether naturally occurring or induced artificially by inoculation), suggesting independent resistance mechanisms may operate in stems and pods. Broad-sense heritability estimates, based on clones common to the two trials, were high (0.85 and 0.63 for stem canker incidence and severity, respectively, and 0.41 for Ppr incidence) indicating a strong influence of host genotype on the response to P . palmivora . [ABSTRACT FROM AUTHOR]

Copyright of Progress in Plant Protection is the property of Institute of Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

A recent survey of cocoa growing areas in India revealed that cocoa stem canker caused by Phytophthora is a serious problem. With the expansion of cocoa growing and the increase in canker incidence it became imperative to develop ecofriendly and economically viable disease management strategies. Field trials were laid out for two years to develop disease management strategies for stem canker of cocoa. There were six treatments with three fungicides viz., mancozeb, copper oxychloride and phosphorous acid, a biocontrol agent, Trichoderma harzianum and cultural practices alone. The treatments were applied only once during December. Though the different treatments except control did not vary significantly, phosphorus acid treatment was found to be better than all other treatments in controlling the disease. The number of active lesions 5 months after the treatment with phosphorous acid and T.harzianum did not vary much. Phosphorous acid (Akomin 40 @ 5ml/L. water) was applied to the wound caused after removing the bark from the canker lesion as well as spraying the whole plant. Coir pith cake seeded with T.harzianum (activated by soaking in water) was applied to the area where only 25cm2 bark surface layer was removed. In addition, five T.harzianum cakes soaked in water were kept at equidistance in the soil around cocoa plants at a distance of 15 cm from the base of the stem and covered with dried leaves of arecanut and cocoa as mulch. Luxurious growth of T.harzianam covered the entire cake after 48 h and had spread to the infected internal tissue. Removal of infected tissues from the canker (cultural practices alone) without any other treatment was also found to be effective in reducing lesion size to some extent. But the number of active lesions after 5 months of this treatment was much higher than all other treatments. Though all the treatments were on par and significantly different from the control, treatment with T.harzianum is expected to be more effective in the long run as the number of active lesions after treatment was less and because this biocontrol agent can survive and multiply under the congenial microclimatic conditions in the garden, thereby suppressing the Phytophthora population in the cropping system. [ABSTRACT FROM AUTHOR]

The article offers information on a study which examines the incidence and severity of stem canker disease in mulberry nurseries of Kolar district in India. A survey was conducted on areas with intensive sericulture during the rainy season of 2006-2007. It states that the disease caused by Lasiodiploda theobromae is the major disease during nursery plantations. It suggests that the nursery must be raised with proper organic inputs and using matured cuttings for propagation.

Copyright of Journal of Plant Protection Research is the property of Institute of Plant Protection and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: Brassica crops used in crop rotations and as green manures have been associated with reductions in soilborne pests and pathogens. These reductions have been attributed to the production of volatile sulfur compounds through a process known as biofumigation, and to changes in soil microbial community structure. In this study, selected Brassica crops, including canola, rapeseed, radish, turnip, yellow mustard, and Indian mustard, were evaluated for control of various soilborne potato pathogens and diseases in culture, in greenhouse trials, and in field trials on commercial potato farms. In in vitro assays, volatiles released from chopped leaf material of Brassica crops and barley inhibited growth of a variety of soilborne pathogens of potato, including Rhizoctonia solani, Phytophthora erythroseptica, Pythium ultimum, Sclerotinia sclerotiorum, and Fusarium sambucinam, with Indian mustard resulting in nearly complete inhibition (80–100%). All Brassica crops and barley reduced inoculum levels of R. solani (20–56% reduction) in greenhouse tests, and radish, rapeseed, and Indian mustard reduced subsequent potato seedling disease by 40–83%. In an on-farm field trial at a site with a substantial powdery scab problem, Indian mustard, rapeseed, canola, and ryegrass grown as green manure rotation crops reduced powdery scab in the subsequent potato crop by 15–40%, and canola and rapeseed reduced black scurf by 70–80% relative to a standard oats rotation. At another field site where common scab was the primary disease problem, an Indian mustard green manure reduced common scab by 25%, and rapeseed, yellow mustard, and ‘Lemtal’ ryegrass also reduced black scurf relative to a standard ryegrass rotation. Disease reductions were not always associated with higher glucosinolate-producing crops, and were also observed with non-Brassica crops (barley and ryegrass), indicating other mechanisms and interactions are important, particularly for control of R. solani. Overall, Indian mustard was most effective for reducing powdery scab and common scab diseases, whereas rapeseed and canola were most effective in reducing Rhizoctonia diseases. These results indicate that Brassica crops have potential for use as green manures for the control of multiple soilborne disease problems. [Copyright &y& Elsevier]

Rhizoctonia solani causes stem canker and significantly impacts potato production. Conventional assay to evaluate potato resistance using R. solani inoculum is time consuming. To establish an effective and fast assay, 20 potato cultivars/lines were examined using both R. solani AG2-1 as an inoculum and its derived toxin (RS toxin). In field trials of 2009 and 2010, wheat-bran-mediated inoculum of R. solani AG2-1 was incorporated at either 0, 2, 3, 4 or 5 g per seed piece in the soil before sowing in the furrow. Stem canker was evaluated sixty-five days after planting. Inoculation at 2, 3, or 4 g R. solani AG2-1 well distinguished resistance of potato cultivars/lines. For a quick assay of resistance screening, a toxin-based method was established by treating potato seedlings with RS toxin of R. solani AG2-1. RS toxin was prepared by heating R. solani AG2-1 culture. Potato seedlings were obtained through tissue culture and grown in Murashige and Skoog medium. Seedlings at the stage of 12 cm in height were transferred into agar amended with RS toxin and incubated for eight days. The level of inhibition caused by RS toxin was positively correlated with toxin concentration. By evaluating various potato cultivars/liens that have different sensitivities to toxin, the inhibition was from 33% to 100% on potato stems sections and from 32% to 148% on seedlings. The toxin-based evaluation was highly correlated with field data using pathogen inoculum (r = 0.731, P < 0.01). Inoculation with wheat bran-mediated R. solani AG2-1 of 2, 3 or 4 g per seed piece was effective in field evaluations. The toxin-based assay improved the efficiency of disease resistance evaluation. Both assays showed that none of the 20 potato cultivars/liens was completely resistant to R. solani AG2-1. However, cultivar 'Desiree' had the lowest level of disease, whereas 'Atlantic', 'Favorita', and 'Shepody' were the most susceptible cultivars. • Rhizoctonia solani toxin is a major contributor to pathogenicity. • The toxin can be used for pathogenicity assay. • The toxin-based method is easy, fast and reliable and can be used for large germplasm screening for disease resistance. [ABSTRACT FROM AUTHOR]