scholarly journals An Evaluation of Cucurbits for Susceptibility to Cucurbitaceous and Solanaceous Phytophthora capsici isolates

Plant Disease ◽  
2012 ◽  
Vol 96 (10) ◽  
pp. 1404-1414 ◽  
Author(s):  
T. B. Enzenbacher ◽  
M. K. Hausbeck
Keyword(s):  
Phytophthora Capsici ◽  
Post Inoculation ◽  
Progress Curve ◽  
Crop Type ◽  
Summer Squash ◽  
Millet Seed ◽  
Oomycete Pathogen ◽  
Potting Media ◽  
Phytophthora Rot ◽  
Winter Squash

Cucumber (Cucumis sativus) and squash (Cucurbita spp.) production in Michigan is limited by the oomycete pathogen Phytophthora capsici. Cucumber, summer squash, and winter squash fruit were evaluated for susceptibility to five isolates of P. capsici. Detached fruit were inoculated with a 5-mm-diameter culture plug of mycelia and sporangia and were incubated in a laboratory or greenhouse. Lesion and pathogen growth diameters were measured and pathogen growth density was visually assessed. All P. capsici isolates incited rot, with significant differences found among fruit type and pathogen isolate. Straightneck squash (Cucurbita pepo), slicing cucumber, and butternut squash (C. moschata) exhibited more severe symptoms than the other fruit tested. Summer and winter squash seedlings were evaluated in greenhouse experiments, in which P. capsici-infested millet seed (approximately 1 g) were placed on the surface of soilless potting media. Disease severity was visually assessed every 2 days for 14 days post inoculation. Crop type, pathogen isolate, or the crop type–pathogen isolate interaction term were significant for symptom appearance and area under the disease progress curve values. Differences in susceptibility of butternut squash and zucchini cultivars were observed following inoculation with solanaceous isolate 13351. Results from this study can refine management programs for Phytophthora rot.

scholarly journals Using Cultural Practices and Cultivar Resistance to Manage Phytophthora Crown Rot on Summer Squash

HortScience ◽  
2012 ◽  
Vol 47 (8) ◽  
pp. 1080-1084 ◽  
Author(s):  
Michael D. Meyer ◽  
Mary K. Hausbeck
Keyword(s):  
Cultural Practices ◽  
Phytophthora Capsici ◽  
Poultry Litter ◽  
Bare Soil ◽  
Crown Rot ◽  
Post Inoculation ◽  
Bed Height ◽  
Progress Curve ◽  
Summer Squash ◽  
Germplasm Accessions

The effects of bed height, mulches, composted poultry litter, and cultivars on Phytophthora crown rot, caused by Phytophthora capsici Leonian, of summer squash (Cucurbita pepo L.) were evaluated in the absence of fungicide applications. The experimental design was a split-split-split plot arrangement of a randomized complete block. Bed height (flat or raised) was the main plot treatment. Mulches (bare soil, wheat straw, or plastic) were subplot treatments. Composted poultry litter applications (0 or 4.5 t·ha−1) were sub-subplot treatments. Squash cultivars (Cougar or Payroll) were sub-sub-subplot treatments. Incidence of plant death (%) was assessed from 0 to 35 days post-inoculation (dpi) with P. capsici. Plant death 35 dpi and area under the disease progress curve (AUDPC)differed significantly (P < 0.0001) between the cultivars Cougar and Payroll. Mean plant death 35 dpi was 87% for ‘Payroll’ and 99% for ‘Cougar’. The bed height × cultivar interaction was also significant (P = 0.0018) in the analyses of variance for plant death and AUDPC. Plant death at 35 dpi and AUDPC for ‘Payroll’ were greater in flat beds than raised beds. Disease was unaffected by the main effects of bed height, mulch type, or application of poultry litter. Thirty-two summer squash cultivars and 10 germplasm accessions were also evaluated for resistance to Phytophthora crown rot in a separate greenhouse trial. Crown rot severity was rated on a 1 (no symptoms) to 5 (plant death) scale at 18 dpi. Crown rot severity differed significantly (P < 0.0001) among cultivars and germplasm accessions. Crown rot severity averaged 4.3 on commercial cultivars and 2.2 on germplasm accessions. Crown rot was least severe on the commercial cultivar Spineless Beauty (mean rating = 2.9). No disease developed on four accessions of Cucurbita moschata previously reported to be crown rot-resistant.

scholarly journals Increased Flower Production of Calibrachoa x hybrida by the Soil Fungus Mortierella elongata1

2020 ◽  
Vol 38 (4) ◽  
pp. 114-119
Author(s):  
Lindsey E. Becker ◽  
Marc A. Cubeta
Keyword(s):  
Populus Deltoides ◽  
Growth Promotion ◽  
Soil Fungus ◽  
Dry Weight ◽  
Post Inoculation ◽  
Flower Production ◽  
Deep Blue ◽  
Millet Seed ◽  
Potting Media ◽  
Mortierella Elongata

Abstract Calibrachoa (Calibrachoa x hybrida) is a highly valued solanaceous flowering ornamental plant, characterized by its drought-hardiness, abundant flowering, and diverse flower colors. Recently, the saprobic soil fungus Mortierella elongata was isolated as a root endophyte from eastern cottonwood (Populus deltoides) and identified as a potential biological amendment for bioenergy and food crops. Two greenhouse experiments were conducted by transplanting rooted cuttings of Calibrachoa cv. ‘Kabloom Deep Blue' into a potting media mixture amended with 1 or 2% volume mix ratio of millet seed colonized with one of four isolates of M. elongata. Plants were assessed weekly for flower production and 86 days post inoculation for leaf/stem, root, and total dry weight. M. elongata strain 624- significantly increased flower production compared to the non-inoculated millet seed controls at 6 and 7 wk post amendment in both experiments. Above and below ground vegetative dry weight for plants grown in potting media mixture amended with M. elongata isolates varied across isolates, fungal amendment concentrations, and experiments. Our results suggest that potting media mixture amended with M. elongata strain 624- can increase flower production of Calibrachoa during peak marketable periods. Index words: Calibrachoa, plant growth promotion, plant reproduction, biological amendment. Species used in this study: Calibrachoa (Calibrachoa x hybrida); Mortierella elongata Linnem.

scholarly journals Age-related Resistance of Diverse Cucurbit Fruit to Infection by Phytophthora capsici

2009 ◽  
Vol 134 (2) ◽  
pp. 176-182 ◽  
Author(s):  
Kaori Ando ◽  
Sue Hammar ◽  
Rebecca Grumet
Keyword(s):  
Cucumis Melo ◽  
Cucurbita Pepo ◽  
Citrullus Lanatus ◽  
Phytophthora Capsici ◽  
Vegetable Production ◽  
Age Related ◽  
Cucumber Fruit ◽  
Summer Squash ◽  
Pronounced Reduction ◽  
Green Stage

Phytophthora capsici causes severe losses in vegetable production, including many cucurbit crops. Our previous work showed that cucumber (Cucumis sativus) fruit are most susceptible to P. capsici when they are very young and rapidly elongating, but develop resistance as they approach full length at 10 to 12 days postpollination (DPP). In this study, fruit from seven additional cucurbit crops representing four species, melon (Cucumis melo), butternut squash (Cucurbita moschata), watermelon (Citrullus lanatus), and zucchini, yellow summer squash, acorn squash, and pumpkin (Cucurbita pepo), were tested for the effect of fruit development on susceptibility to P. capsici. Field-grown fruit of the different crops varied in overall susceptibility. Zucchini and yellow summer squash were the most susceptible, with the majority of fruit exhibiting water-soaking symptoms within 24 hours postinoculation. Fruit from all of the crops exhibited size-related decrease in susceptibility, but to varying degrees. Cucumber had the most pronounced effect. In infested fields, cucumber fruit were found to be most frequently infected at the blossom end. Comparison of the peduncle and blossom end showed a difference in susceptibility along the length of the fruit for cucumber, butternut squash, and zucchini. Greenhouse-grown, hand-pollinated pumpkin, acorn squash, and butternut squash showed an age-related decrease in susceptibility similar to field-grown fruit. For all of these fruit, a pronounced reduction in susceptibility accompanied the transition from the waxy green to green stage at ≈3 to 8 DPP.

scholarly journals Growth and Yields of Bell Pepper and Winter Squash Grown with Organic and Living Mulches

1994 ◽  
Vol 119 (6) ◽  
pp. 1193-1199 ◽  
Author(s):  
Nancy E. Roe ◽  
Peter J. Stoffella ◽  
Herbert H. Bryan
Keyword(s):  
Cucurbita Pepo ◽  
Phytophthora Capsici ◽  
Bell Pepper ◽  
Pepper Plant ◽  
Arachis Glabrata ◽  
Organic Mulch ◽  
Small Seed ◽  
Raised Bed ◽  
Plant Stand ◽  
Winter Squash

Increasing disposal problems with polyethylene (PL) mulch and greater availability of compost prompted an investigation into the effects of using compost as a mulch on horizontal raised bed surfaces with living mulches (LMs) on vertical surfaces. Wood chips (WC), sewage sludge-yard trimming (SY) compost, and municipal solid waste (MW) compost were applied at 224 t·ha-1 on bed surfaces. Sod strips of `Jade' (JD) or `Floratam' (FT) St. Augustinegrass (Stenotaphrum secundatum Kuntze) or perennial peanut (Arachis glabrata Benth.) (PP) or seeds of a small, seed-propagated forage peanut (Arachis sp.) (SP) were established on the vertical sides of the raised beds before transplanting bell pepper (Capsicum annuum L.) into the beds. Phytophthora capsici reduced pepper plant stand in PL-mulched plots compared with organic mulch (OM) and LM. Despite the stand reduction, total pepper yields were highest in PL plots and, in the OM plots, decreased in the order SY > MW > WC. Early fruit yields and yield per plant were highest from plants in PL plots followed by SY. Among LMs, plants in SP plots produced highest early yields and FT produced the lowest. Plants in PL plots produced the largest fruit. When the same plots were seeded with winter (butternut) squash (Cucurbita pepo L.), plant stands were higher in MW than WC and SY. Squash yields were similar between PL and OM plots.

scholarly journals Evaluation of Winter Squash and Pumpkin Cultivars for Age-related Resistance to Phytophthora capsici Fruit Rot

HortScience ◽  
2016 ◽  
Vol 51 (10) ◽  
pp. 1251-1255 ◽  
Author(s):  
Charles S. Krasnow ◽  
Mary K. Hausbeck
Keyword(s):  
Cucurbita Pepo ◽  
Disease Incidence ◽  
Phytophthora Capsici ◽  
Genetic Resistance ◽  
Fruit Rot ◽  
Infested Soil ◽  
Cucurbita Moschata ◽  
Cucurbita Maxima ◽  
Age Related ◽  
Winter Squash

Phytophthora capsici annually threatens production of cucurbit and solanaceous crops. Long-lived oospores produced by the pathogen incite primary infection of susceptible plants when conditions are wet. Limiting the rot of winter squash and pumpkin (Cucurbita sp.) fruits is difficult due to the long maturation period when fruits are often in direct contact with infested soil. Genetic resistance to fruit rot is not widely available within Cucurbita sp.; however, age-related resistance (ARR) to P. capsici fruit rot develops in specific cultivars during maturation. The objective of this study was to evaluate the fruits of 12 cultivars of Cucurbita pepo, Cucurbita moschata, and Cucurbita maxima for ARR to P. capsici using a mycelial-plug inoculation method. All Cucurbita pepo and Cucurbita moschata cultivars displayed ARR; 7 days postpollination (dpp) fruits were susceptible, limited lesion development occurred on fruits 22 dpp, and lesions did not develop at 56 dpp. Disease developed on both Cucurbita maxima cultivars tested at 7, 14, 22, and 56 dpp. Firmness of fruit exocarps was measured with a manual penetrometer. Exocarp firmness of all cultivars increased during maturation; however, there was no correlation between firmness and disease incidence among cultivars at 22 dpp (R2 = −0.01, P = 0.85). When fruits of cultivars expressing ARR at 22 dpp were wounded before inoculation, fruit rot developed.

scholarly journals Resistance of Pepper to Phytophthora Crown, Root, and Fruit Rot Is Affected by Isolate Virulence

Plant Disease ◽  
2010 ◽  
Vol 94 (1) ◽  
pp. 24-30 ◽  
Author(s):  
J. M. Foster ◽  
M. K. Hausbeck
Keyword(s):  
Root Rot ◽  
Laboratory Experiments ◽  
Phytophthora Capsici ◽  
Fruit Rot ◽  
Hot Pepper ◽  
Cultivar Resistance ◽  
Breeding Lines ◽  
Pepper Fruit ◽  
Millet Seed ◽  
Crown And Root Rot

Greenhouse and laboratory experiments were conducted to determine the virulence of four Phytophthora capsici isolates from Michigan to 31 bell and hot pepper cultivars and breeding lines. Resistance to crown and root rot was assessed following the inoculation of soilless media with P. capsici–infested millet seed. In a detached fruit assay, fruit rot resistance was evaluated following inoculation with zoospore suspensions of 1.75 × 106 zoospores/ml. The four isolates differed in virulence to pepper lines screened for crown and root rot resistance and were considered to be four different physiological races. The pepper lines CM334, NY07-8001, NY07-8006, and NY07-8007 were resistant to the isolates tested. None of the commercial cultivars were resistant to P. capsici isolate 12889, but several cultivars were resistant to the other isolates screened. The isolates varied in their ability to cause infection on the fruits of the different cultivars. Overall, pepper fruit were more susceptible to P. capsici than the roots and crowns. Management of Phytophthora crown and root rot of pepper can be improved through the use of resistant cultivars. However, since isolate virulence affects resistance, cultivar resistance will need to be utilized on a local scale accordingly.

scholarly journals Penetration and post-infection development of root-knot nematodes in watermelon

2018 ◽  
Vol 15 (4) ◽  
pp. e1010 ◽  
Author(s):  
Manuel López-Gómez ◽  
Soledad Verdejo-Lucas
Keyword(s):  
Life Cycle ◽  
Post Infection ◽  
Egg Laying ◽  
Initial Population ◽  
Post Inoculation ◽  
Second Stage ◽  
Progress Curve ◽  
Third Stage ◽  
Reproduction Factor ◽  
Nematode Development

Meloidogyne javanica has showed less reproductive success than M. incognita in watermelon genotypes. This study was conducted to elucidate the low reproduction of M. javanica in watermelon. The post-infection development of M. javanica in watermelon ‘Sugar Baby’ was determined at progressively higher initial population (Pi) levels at two time points during the life cycle. Plants were inoculated with 0, 25, 50, 100, 200, and 300 second-stage juveniles (J2)/plant. The increase in Pi was correlated with the penetration rates (R2= 0.603, p<0.001) and total numbers of nematodes in the root (R2 =0.963, p< 0.001) but there was no correlation between the Pi and the reproduction factor (eggs/plant/Pi). The population in the roots at 26 days post-inoculation (dpi) consisted primarily of third-stage juveniles (J3) with a small presence of J2 and fourth stages, and egg-laying females. The dominance of the J3, when egg-laying females are expected, point to the malfunction of the feeding sites that failed to support nematode development beyond the J3 stage. The similarities in egg-laying females at 26 and 60 dpi imply the disruption of the life cycle. Watermelon compensated for M. javanica parasitism by increasing vine length (19% to 33%) and dry top weight (40%) in comparison with the non-inoculated plants. The area under the vine length progress curve was significantly larger as the Pi progressively increased (R²=0.417, p<0.001). Physiological variation was detected between the M. incognita populations. M. arenaria had less ability to invade watermelon roots than did M. incognita and M. javanica.

scholarly journals Performance and Resistance to Phytophthora Crown and Root Rot in Squash Lines

2020 ◽  
Vol 30 (5) ◽  
pp. 608-618 ◽  
Author(s):  
Kyle E. LaPlant ◽  
Gregory Vogel ◽  
Ella Reeves ◽  
Christine D. Smart ◽  
Michael Mazourek
Keyword(s):  
Root Rot ◽  
Cucurbita Pepo ◽  
Field Experiments ◽  
Phytophthora Capsici ◽  
Severe Disease ◽  
Field Trials ◽  
Disease Symptoms ◽  
Resistant Lines ◽  
Oomycete Pathogen ◽  
Crown And Root Rot

Phytophthora crown and root rot, caused by the oomycete pathogen Phytophthora capsici, is a devastating disease of squash and pumpkin (Cucurbita pepo). No currently available cultivars provide complete resistance to this disease. Three newly developed squash lines and four hybrids were evaluated in greenhouse and field experiments for their resistance to phytophthora crown and root rot as well as for their horticultural performance. The three newly developed lines ranked among the most resistant entries included in 2 years of field trials. In addition, in a separate greenhouse experiment, one of the lines was shown to display the least severe disease symptoms among a group of accessions previously reported to possess partial resistance to phytophthora crown and root. Furthermore, the resistance was observed to be robust to several isolates of P. capsici. However, the phytophthora-resistant lines had reduced yield relative to standard squash cultivars. These lines are useful for continued breeding efforts toward a phytophthora crown and root rot-resistant cultivar.

scholarly journals Vegetable Variety Trial Programs: Opportunities and Challenges at Auburn University

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 503E-504
Author(s):  
J.M. Kemble ◽  
E. Simonne
Keyword(s):  
Late Summer ◽  
Nutritional Composition ◽  
Postharvest Quality ◽  
Variety Trial ◽  
Summer Squash ◽  
County Agents ◽  
Rapid Dissemination ◽  
Growing Environment ◽  
Dissemination Of Results ◽  
Winter Squash

In 1996, more than 72,000 acres of vegetables were produced in Alabama. This number has been steadily increasing since the mid-1980s. Growers and county agents requested information on which vegetable varieties performed well in Alabama. To support a growing vegetable industry, Auburn Univ. committed itself to developing an extensive vegetable variety trial (VVT) program focusing on rapid dissemination of results. Presently, replicated trials are held at nine experiment stations, each representing a unique growing environment. The VVTs are divided into a spring and fall section. The spring trials evaluate spring/summer planted crops such as tomato, peppers, watermelon, sweetpotato, eggplant, southernpea, lettuce, melons, cucumber, summer squash, and others. Fall trials examine cole crops, winter squash, pumpkin, and other late-summer/fall-planted crops. Turn around time from final harvest of the final crop to placing the report in the county agent's or grower's hands is 2 to 3 months. Good support is received from industry through financial contributions and/or materials. More than 3000 copies of the spring and fall VVT reports are distributed annually at field days, statewide and county meetings, and in direct mailings. Other research projects, such as projects on nutritional composition of vegetables, postharvest quality, and consumer acceptance, have been supported by materials from the VVT program. Without overwhelming support and commitment from the State of Alabama, Auburn Univ., grower organizations, and industry, the VVT program would not be the success that it is today providing timely and needed information to strengthen the growing vegetable industry in Alabama.

scholarly journals INDUCTION OF DEFENSE MECHANISMS IN TOMATO PLANTS BY SAPROBIC FUNGI FILTRATES AGAINST EARLY BLIGHT DISEASE

2020 ◽  
Vol 33 (3) ◽  
pp. 671-678
Author(s):  
MARIANNA SANTOS RODRIGUES ALENCAR ◽  
ANTÔNIO JUSSIÊ DA SILVA SOLINO ◽  
JULIANA SANTOS BATISTA OLIVEIRA ◽  
SÉRGIO FLORENTINO PASCHOLATI ◽  
KÁTIA REGINA FREITAS SCHWAN-ESTRADA
Keyword(s):  
Polyphenol Oxidase ◽  
Early Blight ◽  
Specific Activity ◽  
Lipoxygenase Activity ◽  
Post Inoculation ◽  
Pycnoporus Sanguineus ◽  
Tomato Plants ◽  
Saprobic Fungi ◽  
Progress Curve ◽  
Blight Disease

ABSTRACT Tomato plants can be attacked by several diseases. The early blight disease causes large losses to tomato growers and requires many applications of fungicide for its control. Thus, the objective of this work was to evaluate the effect of saprobic fungi filtrates on the control of early blight (Alternaria solani) in tomato plants. The treatments consisted of fungi filtrates (Stachylidium bicolor - SBI; Periconia hispidula - PHI; Brachysporiella pulchra - BPU; Myrothecium leucotrichum - MLE; and Pycnoporus sanguineus - PSA) diluted at 20%, a control (water), and acibenzolar-S-methyl (ASM). Tomato plants with five leaves were treated with the filtrates, and A. solani was inoculated after three days. The variables analyzed were: area under the disease progress curve (AUDPC), and specific activity of the enzymes: catalase, lipoxygenase, peroxidase, and polyphenol oxidase. The SBI filtrate decreased the AUDPC in 80% for the third leaf and 96% for the fourth leaf. Catalase activity increased due to the application of BPU and PHI filtrates, at 96 hours post-inoculation (hpi). Lipoxygenase activity increased in 130%, 72%, 130%, and 81% at 24 hpi when applying the SBI, PHI, MLE, and ASM filtrates, respectively. The application of SBI, BPU, MLE, and PSA filtrates increased lipoxygenase activity in 30%, 26%, 12%, and 22%, respectively, at 120 hpi. Peroxidase activity increased 74% at 120 hpi, when applying the SBI filtrate. Polyphenol oxidase activity was not affected by the treatments. S. bicolor filtrate is efficient to control the severity of the early blight disease in tomato plants.

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