scholarly journals THE EGGPLANT BLIGHT AND FRUIT ROT IN PORTO RICO

1969 ◽  
Vol 13 (2) ◽  
pp. 35-57
Author(s):  
J. A. B. Nolla
Keyword(s):  
Bordeaux Mixture ◽  
Control Measure ◽  
Soil Surface ◽  
The United States ◽  
Labor Cost ◽  
Fruit Rot ◽  
Seedling Blight ◽  
Stem Blight ◽  
Phomopsis Vexans ◽  
Serious Disease

1. A serious disease of eggplants known in Porto Rico as "lunares de la hoja y tallo" and "podredumhre de la fruta", in the United States of North America as leaf blight, foot-rot, leaf-spot, stem-blight. fruit-rot, eggplant-blight and seedling-stem-blight and in Cuba as "mancha de la hoja" and "enfermedad del tallo" exists in Porto Rico. 2. All varieties of eggplant are more or less equally susceptible under Porto Rican conditions. Color of plant or of fruit has no bearing on susceptibility or resistance. 3. The disease usually brings a loss of 50 per cent or over of the crop. 4. The symptoms of the disease appear on all above-ground parts of the plant. A seedling blight, stem and petiole cankers, spots on leaf blades, fruit stalks and calices and a rotting of the young and mature fruit are produced. 5. The fungus may occur inside the seed. 6. The pathogene responsible for the malady is Phomopsis vexans (Sacc. & Sydow) Harter. 7. Variations of the fungus as have been observed elsewhere do not appear to occur in the fungus in Porto Rico. 8. The size of the pyenidiospores ranges from 5 to 8 microns in length to 1.3 to 3 microns in width. 9. The germ tube of a germinating spore may either enter through a stoma, enter through a wound or force its penetration through the cuticle. 10. Secondary cycles repeatedly occur in fields. 11. The fungus is capable of a saprophytic existence. 12. The prevailing temperature in Porto Rico seems adequate for spore germination. 13. Moisture is a very important factor in outbreaks of the disease. 14. The disease is probably controlled by a three- or four-years rotation. 15. Plants with the symptoms of the disease should be promptly removed from fields. 16. Although seed treatment is beneficial it never completely eliminates the pathogene. 17. Clean seed from unaffected fruit should be demanded. 18. Infested soils should be avoided in preparing seedbeds. 19. Inoculated soils can he rendered safe for seedlings if drenched with a 1-50 formaldehyde solution at the rate of one-half gallon per square foot of soil surface. An application of 4-4-50 Bordeaux mixture is highly beneficial but the formaldehyde treatment is to be preferred. The latter treatment will cost about two-thirds of one cent per seedling. 20. Bordeaux mixture (4-4-50) is quite effective in preventing seedling blight. The treatment is too expensive and therefore inapplicable under ordinary conditions. Bordeaux mixture may be of practical application where labor cost is reduced. The safest and cheapest control measure is to grow healthy seedlings and set them on in uninfested soils.

scholarly journals Development of Phytophthora Fruit Rot Caused by Phytophthora capsici on Resistant and Susceptible Watermelon Fruit of Different Ages

Plant Disease ◽  
2018 ◽  
Vol 102 (2) ◽  
pp. 370-374 ◽  
Author(s):  
Chandrasekar S. Kousik ◽  
Jennifer L. Ikerd ◽  
William W. Turechek
Keyword(s):  
South Carolina ◽  
Phytophthora Capsici ◽  
The United States ◽  
Fruit Rot ◽  
Breeding Programs ◽  
Lesion Diameter ◽  
Agar Plug ◽  
Resistant Lines ◽  
Different Ages ◽  
Serious Disease

Watermelon is an important crop grown in 44 states in the United States. Phytophthora fruit rot caused by Phytophthora capsici is a serious disease in the southeastern U.S.A., where over 50% of the watermelons are produced. The disease has resulted in severe losses to watermelon growers, especially in Georgia, South Carolina, and North Carolina during the past few years. Several fruit rot-resistant watermelon germplasm lines have been developed for use in breeding programs. To evaluate the development of Phytophthora fruit rot on fruit of different ages, plants of fruit rot-resistant and susceptible lines were planted at weekly intervals for five consecutive weeks in experiments conducted over three years (2011 to 2013). Flowers were routinely inspected and hand pollinated to ensure having fruit of different ages. In each year, different aged fruit were harvested on the same day and inoculated with a 5-mm agar plug from an actively growing colony of P. capsici. Inoculated fruit were maintained in a room set to conditions conducive for disease development (>95% relative humidity, 26 ± 2°C). After 5 days, lesion diameter and intensity of sporulation was recorded for each fruit. Lesion diameter and sporulation intensity were significantly greater on fruit of susceptible lines compared with resistant lines. Fruit age did not have an effect on either measurement on susceptible (Sugar Baby) or resistant lines (PI 560020 and PI 595203). Our results showed that resistance to Phytophthora fruit rot in watermelon was not correlated with fruit age.

scholarly journals Evaluation of a Diverse, Worldwide Collection of Wild, Cultivated, and Landrace Pepper (Capsicum annuum) for Resistance to Phytophthora Fruit Rot, Genetic Diversity, and Population Structure

2015 ◽  
Vol 105 (1) ◽  
pp. 110-118 ◽  
Author(s):  
R. P. Naegele ◽  
A. J. Tomlinson ◽  
M. K. Hausbeck
Keyword(s):  
Genetic Diversity ◽  
Population Structure ◽  
Phytophthora Capsici ◽  
The United States ◽  
Fruit Rot ◽  
Sources Of Resistance ◽  
Plant Introductions ◽  
Genetic Clusters ◽  
Commercial Breeding ◽  
Moderately Resistant

Pepper is the third most important solanaceous crop in the United States and fourth most important worldwide. To identify sources of resistance for commercial breeding, 170 pepper genotypes from five continents and 45 countries were evaluated for Phytophthora fruit rot resistance using two isolates of Phytophthora capsici. Genetic diversity and population structure were assessed on a subset of 157 genotypes using 23 polymorphic simple sequence repeats. Partial resistance and isolate-specific interactions were identified in the population at both 3 and 5 days postinoculation (dpi). Plant introductions (PIs) 640833 and 566811 were the most resistant lines evaluated at 5 dpi to isolates 12889 and OP97, with mean lesion areas less than Criollo de Morelos. Genetic diversity was moderate (0.44) in the population. The program STRUCTURE inferred four genetic clusters with moderate to very great differentiation among clusters. Most lines evaluated were susceptible or moderately susceptible at 5 dpi, and no lines evaluated were completely resistant to Phytophthora fruit rot. Significant population structure was detected when pepper varieties were grouped by predefined categories of disease resistance, continent, and country of origin. Moderately resistant or resistant PIs to both isolates of P. capsici at 5 dpi were in genetic clusters one and two.

scholarly journals First Report of Sclerotinia sclerotiorum on Campanula carpatica and Schizanthus × wisetonensis in Italy

Plant Disease ◽  
2002 ◽  
Vol 86 (1) ◽  
pp. 71-71
Author(s):  
A. Garibaldi ◽  
A. Minuto ◽  
M. L. Gullino
Keyword(s):  
United States ◽  
Sclerotinia Sclerotiorum ◽  
Ornamental Plants ◽  
Soil Surface ◽  
The United States ◽  
First Report ◽  
Potted Plants ◽  
Initial Symptoms ◽  
Stem Necrosis ◽  
Campanula Carpatica

The production of potted ornamental plants is very important in the Albenga Region of northern Italy, where plants are grown for export to central and northern Europe. During fall 2000 and spring 2001, sudden wilt of tussock bellflower (Campanula carpatica Jacq.) and butterfly flower (Schizanthus × wisetonensis Hort.) was observed on potted plants in a commercial greenhouse. Initial symptoms included stem necrosis at the soil line and yellowing and tan discoloration of the lower leaves. As stem necrosis progressed, infected plants growing in a peat, bark compost, and clay mixture (70-20-10) wilted and died. Necrotic tissues were covered with whitish mycelia that produced dark, spherical (2 to 6 mm diameter) sclerotia. Sclerotinia sclerotiorum was consistently recovered from symptomatic stem pieces of both plants disinfested for 1 min in 1% NaOCl and plated on potato dextrose agar amended with streptomycin sulphate at 100 ppm. Pathogenicity of three isolates obtained from each crop was confirmed by inoculating 45- to 60-day-old C. carpatica and Schizanthus × wisetonensis plants grown in containers (14 cm diameter). Inoculum that consisted of wheat kernels infested with mycelia and sclerotia of each isolate was placed on the soil surface around the base of previously artificially wounded or nonwounded plants. Noninoculated plants served as controls. All plants were maintained outdoors where temperatures ranged between 8 and 15°C. Inoculated plants developed symptoms of leaf yellowing, followed by wilt, within 7 to 10 days, while control plants remained symptomless. White mycelia and sclerotia developed on infected tissues and S. sclerotiorum was reisolated from inoculated plants. To our knowledge, this is the first report of stem blight of C. carpatica and Schizanthus × wisetonensis caused by S. sclerotiorum in Italy. The disease was previously observed on C. carpatica in Great Britain (2) and on Schizanthus sp. in the United States (1). References: (1) D. F. Farr et al. Fungi on Plants and Plant Products in the United States. The American Phytopathological Society, St. Paul, MN, 1989. (2) J. Rees. Welsh J. Agric. 1:188, 1925.

scholarly journals First Report of Anthracnose Caused by Colletotrichum acutatum on Persimmon Fruit in the United States

Plant Disease ◽  
2010 ◽  
Vol 94 (5) ◽  
pp. 634-634 ◽  
Author(s):  
S. M. Williamson ◽  
T. B. Sutton
Keyword(s):  
United States ◽  
Filter Paper ◽  
The United States ◽  
Grocery Store ◽  
Fruit Rot ◽  
Colletotrichum Acutatum ◽  
Diospyros Kaki ◽  
Japanese Persimmon ◽  
First Report ◽  
Persimmon Fruit

Persimmon trees are important for their fruit as well as their colorful fruit and foliage in the fall. Persimmon fruit (Japanese persimmon, Diospyros kaki cv. Fuyu) were collected in November 2008 from a tree in Windsor, NC, located in the Coastal Plain. Fruit were not symptomatic on the tree but developed dark lesions after harvest. Isolations from six fruit yielded seven isolates of Colletotrichum acutatum J. H. Simmonds. After incubation at 25°C under continuous light for 15 days on potato dextrose agar (PDA), all isolates had gray aerial mycelium, but the inverse sides of the plates of six isolates were maroon and one was beige. Masses of salmon-colored conidia were formed first in the center of the colonies, then were observed scattered across the colonies in older cultures. Conidia were hyaline, one-celled, elliptic with one or both ends pointed, and measured 8.1 to 16.3 × 3.1 to 5 μm. Setae and sclerotia were not observed. There were also dark structures measuring 1 to 10 mm that were partially embedded in the agar that contained conidia. Cultural and conidial characteristics of the isolates were similar to those of C. acutatum (3). PCR amplification was performed with the species-specific primer pair CaInt2/ITS4 (2) and genomic DNA from the original isolates and isolates obtained from inoculated fruit. An amplification product of approximately 490 bp, which is specific for C. acutatum, was observed. To fulfill Koch's postulates, persimmon fruit obtained from the grocery store were surface disinfested with 0.5% sodium hypochlorite and sterile filter paper disks dipped in conidial suspensions (1 × 105 conidia/ml) of two C. acutatum isolates (maroon and beige reverse) or sterile, deionized water were placed on the fruit. Three fruit were inoculated per treatment and the disks were placed on four locations on each fruit. Parafilm was wrapped around the diameter of the fruit to keep the filter paper disks moist and in place. Fruit were placed in moist chambers and incubated at 25°C. After 3 days, the Parafilm was removed and the fruit returned to the moist chambers. Small, dark lesions were observed on fruit inoculated with each isolate of C. acutatum when the filter paper disks were removed. Ten days after inoculation, dark lesions and acervuli with salmon-colored masses of conidia were observed on fruit inoculated with both isolates of C. acutatum and the fruit were soft. After 12 days, there were abundant masses of conidia and the inoculated areas were decayed. Control fruit remained firm and did not develop symptoms. Cultures obtained from the fruit and the conidia produced were typical of the isolates used to inoculate the fruit. C. acutatum has been reported to cause fruit rot on persimmon fruit in New Zealand (1). To our knowledge, this is the first report of C. acutatum on persimmon fruit in the United States. References: (1) R. Lardner et al. Mycol. Res. 103:275, 1999. (2) S. Sreenivasaprasad et al. Plant Pathol. 45:650, 1996. (3) B. C. Sutton. Page 523 in: Coelomycetes. Commonwealth Agricultural Bureaux, Great Britain. 1980.

scholarly journals Fungicide Rotation Programs for Managing Phytophthora Fruit Rot of Watermelon in Southeastern United States

2017 ◽  
Vol 18 (1) ◽  
pp. 28-34 ◽  
Author(s):  
Chandrasekar (Shaker) S. Kousik ◽  
Pingsheng Ji ◽  
Daniel S. Egel ◽  
Lina M. Quesada-Ocampo
Keyword(s):  
United States ◽  
South Carolina ◽  
Phytophthora Capsici ◽  
Southeastern United States ◽  
Heavy Rain ◽  
Integrated Approach ◽  
The United States ◽  
Fruit Rot ◽  
Management Options ◽  
Before And After

About 50% of the watermelons in the United States are produced in the southeastern states, where optimal conditions for development of Phytophthora fruit rot prevail. Phytophthora fruit rot significantly limits watermelon production by causing serious yield losses before and after fruit harvest. Efficacy of fungicide rotation programs and Melcast-scheduled sprays for managing Phytophthora fruit rot was determined by conducting experiments in Phytophthora capsici-infested fields at three locations in southeastern United States (North Carolina, South Carolina, and Georgia). The mini seedless cultivar Wonder and seeded cultivar Mickey Lee (pollenizer) were used. Five weekly applications of fungicides were made at all locations. Significant fruit rot (53 to 91%, mean 68%) was observed in the nontreated control plots in all three years (2013 to 2015) and across locations. All fungicide rotation programs significantly reduced Phytophthora fruit rot compared with nontreated controls. Overall, the rotation of Zampro alternated with Orondis was highly effective across three locations and two years. Rotations of Actigard followed by Ranman+Ridomil Gold, Presidio, V-10208, and Orondis, or rotation of Revus alternated with Presidio were similarly effective. Use of Melcast, a melon disease-forecasting tool, may occasionally enable savings of one spray application without significantly impacting control. Although many fungicides are available for use in rotations, under very heavy rain and pathogen pressure, the fungicides alone may not offer adequate protection; therefore, an integrated approach should be used with other management options including well-drained fields.

scholarly journals The Changing Link between Labor Cost and Price Inflation in the United States

2021 ◽  
Author(s):  
Elena Bobeica ◽  
Matteo Ciccarelli ◽  
Isabel Vansteenkiste
Keyword(s):  
United States ◽  
The United States ◽  
Labor Cost ◽  
Price Inflation

Ethylene: A Witchweed Seed Germination Stimulant

Weed Science ◽  
1975 ◽  
Vol 23 (5) ◽  
pp. 433-436 ◽  
Author(s):  
Robert E. Eplee
Keyword(s):  
United States ◽  
Seed Germination ◽  
Clay Soil ◽  
Soil Surface ◽  
Field Studies ◽  
The United States ◽  
Major Contributor ◽  
Single Treatment ◽  
Striga Asiatica ◽  
Heavy Clay

Ethylene gas (C2H4) was found to stimulate the germination of witchweed [Striga asiatica(L.) O. Kuntze] seeds. Ethylene diffuses greater than 120 cm horizontally from point of injection and more than 90 cm below the soil surface. Rates of 0.42 kg/ha induced germination of witchweed seeds in sandy soil; but 1.1 kg/ha is required on a heavy clay soil. Witchweed seeds respond to ethylene after a period of preconditioning that is necessary to break dormancy. Under field conditions in the Carolinas, maximum response of seeds to ethylene occurs between late April and late July. Field studies indicate a 90% reduction in viable witchweed seeds occurs where a single treatment with ethylene has been applied. The use of ethylene appears now to be a major contributor toward the eventual eradication of witchweed from the United States.

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