Environmental Effects on MSMA Phytotoxicity to Wild-Type and Arsenical Herbicide-Resistant Common Cocklebur (Xanthium strumarium)

1996 ◽  
Vol 10 (4) ◽  
pp. 809-814 ◽  
Author(s):  
Chandrashekhar I. Nimbal ◽  
David R. Shaw ◽  
Gene D. Wills ◽  
Stephen O. Duke
Keyword(s):  
Relative Humidity ◽  
Xanthium Strumarium ◽  
Wild Type ◽  
Fresh Weight ◽  
Low Light ◽  
Herbicide Resistant ◽  
Effects Of Temperature ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Weed Resistance

Effects of temperature, relative humidity, and light on MSMA phytotoxicity to wild-type and arsenical herbicide-resistant biotypes of common cocklebur grown from seed collected in Mississippi were evaluated. In growth chamber studies, 20-d-old plants were sprayed with 0.5 kg ai/ha of MSMA, and after 7 d, fresh weight and chlorophyll content were measured to estimate phytotoxicity. All three environmental factors influenced the level of weed resistance. In studies with day/night temperatures of 30/25 C and 500 μmol/m2/s PPFD light with a 14-h photoperiod, phytotoxicity of MSMA at 40% relative humidity was minimal, but was significantly greater at 60 and 90% relative humidities. The resistant (R) biotype was affected less than the susceptible (S) biotype at the higher relative humidities. The level of resistance estimated by fresh weight reduction was greatest at 30/25 C, but was most pronounced at 35/30 C using chlorophyll measurements. Resistance was lowest at 25/20 C by either measurement. MSMA phytotoxicity occurred at light intensities of 75, 500, and 750 μmol/m2/s PPFD; however, biotypic response was greatest at 500, followed by 750 μmol/m2/s PPFD. Resistance of the (R) biotype to MSMA was not significant at 75 μmol/m2/s, suggesting that differentiation between the biotypes for MSMA sensitivity would be difficult under low light.

scholarly journals Inoculation Method, Temperature, and Relative Humidity Affect Leaf and Neck Anthracnose, a New Onion Disease in Michigan

2018 ◽  
Vol 19 (1) ◽  
pp. 64-68
Author(s):  
Lina M. Rodriguez-Salamanca ◽  
Rachel P. Naegele ◽  
Lina M. Quesada-Ocampo ◽  
Mary K. Hausbeck
Keyword(s):  
Relative Humidity ◽  
Disease Severity ◽  
Colletotrichum Coccodes ◽  
Conidial Suspension ◽  
New Disease ◽  
Inoculation Method ◽  
Millet Seed ◽  
Effects Of Temperature ◽  
Chamber Studies ◽  
Growth Chamber Studies

Leaf and neck anthracnose caused by Colletotrichum coccodes is a new disease of onion in Michigan. To test the effect of inoculation method, Prince onion seedlings were grown in the greenhouse and inoculated with either a conidial suspension of C. coccodes (alone or with an abrasive agent) or infested millet seed (dry or wet, 2 or 5 g). Foliar disease severity was greater when a conidial suspension (>39%) was used compared with infested millet seed (≤24.3%). Growth chamber studies were conducted using Infinity onion seedlings that were inoculated with a conidial suspension spray to determine the effects of temperature (15, 20, 25, or 30°C) and duration (0, 12, 24, 48, or 72 h) of high (95 ± 5%) relative humidity (RH) on disease severity (percentage of leaf area with C. coccodes lesions). Significant differences and interactions among temperature and RH were observed. The combination of high temperature (≥25°C) and extended (≥24 h) high RH resulted in >20% disease severity 28 days postinoculation. Results suggest that onion leaf and neck anthracnose symptoms are likely to be more severe when the environmental conditions are ≥25°C with ≥24 h of high RH.

Variation in Growth Habit and Response to Chemicals among Three Common Cocklebur (Xanthium strumarium) Selections

Weed Science ◽  
1982 ◽  
Vol 30 (4) ◽  
pp. 339-343 ◽  
Author(s):  
Robert N. Andersen
Keyword(s):  
Growth Habit ◽  
Main Stem ◽  
Growth Chamber ◽  
Xanthium Strumarium ◽  
Leaf Necrosis ◽  
Chamber Studies ◽  
Growth Chamber Studies

Burs of common cocklebur (Xanthium strumarium L.) obtained from Stoneville, Mississippi; Urbana, Illinois; and Lamberton, Minnesota, were used in greenhouse and growth chamber studies. The Mississippi and the Illinois strains were both classified as being in the “strumarium” complex of X. strumarium, whereas, the Minnesota strain was classified as being in the “hybrid” complex. The Minnesota common cocklebur developed branch leaves in the leaf axils of the main stem to a much greater extent than did the Mississippi and Illinois common cocklebur. The Mississippi common cocklebur was frequently more tolerant of postemergence applications of bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] than were the Illinois and Minnesota common cockebur. The Mississippi and Illinois common cocklebur developed leaf necrosis when sprayed with an insecticide formulation containing malathion (o, o-dimethyl phosphorodithioate of mercaptosuccinate) and petroleum solvents; the Minnesota common cocklebur did not.

Anthracnose of Florida Beggarweed (Desmodium tortuosum) Caused byColletotrichum truncatum

Weed Science ◽  
1988 ◽  
Vol 36 (3) ◽  
pp. 329-334 ◽  
Author(s):  
John Gardina ◽  
Robert H. Littrell ◽  
Richard T. Hanlin
Keyword(s):  
Relative Humidity ◽  
Host Specificity ◽  
Plant Species ◽  
Fungal Pathogen ◽  
Disease Development ◽  
Colletotrichum Truncatum ◽  
Optimum Conditions ◽  
Cotyledon Stage ◽  
Chamber Studies ◽  
Growth Chamber Studies

Greenhouse and growth chamber studies were conducted to determine conditions for infection of the fungal pathogenColletotrichum truncatum(Schw.) Andrus and Moore on Florida beggarweed (Desmodium tortuosum(Sw.) DC. # DEDTO and to determine the host specificity of this fungus. Optimum conditions for disease development were 14 to 16 h incubation in 100% relative humidity (RH) at 24 to 29 C. Control of Florida beggarweed with 105to 107C. truncatumspores/ml was greatest in the cotyledon stage and decreased with plant age. Ten of 18Desmodiumspecies tested were susceptible to the Florida beggarweed isolate ofC. truncatumbut 13 other plant species and varieties were resistant and 61 were immune.

INFLUENCE OF LIGHT AND TEMPERATURE ON METRIBUZIN PHYTOTOXICITY TO TOMATO

1973 ◽  
Vol 53 (4) ◽  
pp. 843-847 ◽  
Author(s):  
S. C. PHATAK ◽  
G. R. STEPHENSON
Keyword(s):  
Lycopersicon Esculentum ◽  
High Light ◽  
Growth Chamber ◽  
Low Light ◽  
Factors Associated ◽  
Tert Butyl ◽  
Lycopersicon Esculentum Mill ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Temperature Factors

Growth-chamber studies were conducted to identify the light and temperature factors associated with metribuzin (4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)one) injury to tomatoes (Lycopersicon esculentum Mill.). Plants exposed to 4 days of low light (6,500 lx) were more susceptible to metribuzin injury than those grown in high light (22,000 lx). Injury to tomatoes was greatest under conditions of low light prior to and high light after application of metribuzin to the foliage. Every increase in temperature from 21 C days and 13 C nights, to 25 C days and 18 C nights, to 27 C days and 18 C nights resulted in increased metribuzin injury to tomato.

Influence of Light and Temperature on Bentazon Phytotoxicity to Cucumber (Cucumis sativus)

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 232-235 ◽  
Author(s):  
John R. Teasdale ◽  
Richard W. Thimijan
Keyword(s):  
Cucumis Sativus ◽  
Light Level ◽  
High Light ◽  
Growth Chamber ◽  
Low Light ◽  
Temperature Conditions ◽  
Chamber Studies ◽  
Growth Chamber Studies

In greenhouse and growth-chamber studies, increasing the level of either light or temperature increased bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] phytotoxicity to cucumber (Cucumis sativusL.). Light had a greater influence on phytotoxicity than did temperature. Light and temperature conditions after bentazon application had a greater influence on phytotoxicity than did light and temperature conditions before application. Maximum phytotoxicity was obtained from treatment with low light level before application and high light level after application.

Growth Responses in Sorghum and Wheat Induced by Glyphosate

Weed Science ◽  
1977 ◽  
Vol 25 (3) ◽  
pp. 238-240 ◽  
Author(s):  
J.R. Baur ◽  
R.W. Bovey ◽  
J.A. Veech
Keyword(s):  
Foliar Application ◽  
Normal Growth ◽  
Growth Zone ◽  
Growth Conditions ◽  
Optimum Growth ◽  
Growth Responses ◽  
Fresh Weight ◽  
Optimum Growth Temperature ◽  
Chamber Studies ◽  
Growth Chamber Studies

Foliar application of 2.8 μg/plant of glyphosate [N-(phosphonomethyl)glycine] to greenhouse grown sorghum [Sorghum bicolor (L.) Moench ‘Tophand’] seedlings resulted in increased fresh weight. As glyphosate levels were increased to 11.2 μg/plant, diameter of the basal growth zone increased while fresh weight decreased. In growth chamber studies with sorghum and wheat [Triticum aestivum (L.) ‘Era’] seedlings, glyphosate caused the greatest reduction in fresh weight at the optimum growth temperatures for both species. Glyphosate inhibited normal production of basal buds in wheat at the optimum growth temperature and stimulated bud production at temperatures above the optimum. Under normal growth conditions, basal buds in sorghum do not develop; however, application of glyphosate stimulated basal bud development under normal and above-normal temperature conditions. Histochemical analysis of malate dehydrogenase activity in apical meristem tissue of treated sorghum seedlings indicated that growth of the apex was normal and viable.

scholarly journals Influence of Temperature, Relative Humidity, Ascospore Concentration, and Length of Drying of Colonized Dry Bean Flowers on White Mold Development

Plant Disease ◽  
2006 ◽  
Vol 90 (7) ◽  
pp. 946-950 ◽  
Author(s):  
R. Harikrishnan ◽  
L. E. del Río
Keyword(s):  
Relative Humidity ◽  
Linear Increase ◽  
White Mold ◽  
Post Inoculation ◽  
Disease Development ◽  
Dry Bean ◽  
Influence Of Temperature ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Inoculum Type

Growth chamber studies were conducted using rehydrated dry bean (Phaseolus vulgaris) flowers (RDBF) to assess the influence of temperature (18 and 22°C), relative humidity (RH; 25 and 90%), and ascospore concentrations (102, 103, and 104 ascospores/ml) on white mold incidence in dry bean. Additional studies were carried out to determine the influence of inoculum type (ascospore and mycelium) and to estimate the effect of duration of drying of colonized RDBF on viability of Sclerotinia sclerotiorum and white mold incidence. There was a linear increase in white mold incidence with increase in ascospore concentration but neither temperature nor RH levels significantly affected disease development. In the inoculum type study, both temperature and RH levels significantly affected white mold incidence; however, neither ascospore nor mycelial inocula had a significant effect on white mold incidence. Drying colonized RDBF for up to 96 h did not affect S. sclerotiorum viability; but the amount of white mold incidence depended more on post-inoculation RH and drying duration than on the temperatures tested. Colonized RDBF dried for 96 h took approximately three times longer to achieve 100% white mold incidence compared with colonized RDBF dried for 24 h. These results suggest the potential for greater white mold development with higher ascospore availability and the potential of dry S. sclerotiorum-colonized dry bean flowers as a viable inoculum source.

scholarly journals Effects of Temperature, Humidity, and Wounding on Development of Phytophthora Rot of Cucumber Fruit

Plant Disease ◽  
2010 ◽  
Vol 94 (12) ◽  
pp. 1417-1424 ◽  
Author(s):  
L. L. Granke ◽  
M. K. Hausbeck
Keyword(s):  
Relative Humidity ◽  
Phytophthora Capsici ◽  
Fruit Size ◽  
Fruit Rot ◽  
Age Related ◽  
Cucumber Fruit ◽  
Wide Range ◽  
Pickling Cucumbers ◽  
Effects Of Temperature ◽  
Growth Chamber Studies

The effects of temperature (10, 15, 20, 25, 30, and 35°C) and relative humidity (~35, 60, 70, 80, and 100%) on development of Phytophthora fruit rot, caused by Phytophthora capsici, of pickling cucumber (Cucumis sativus) were investigated in controlled growth chamber studies. The effect of wounding on disease development was characterized for small (2.0 to 2.5 cm diameter × 8 to 9 cm long), medium (3.0 to 4.0 cm diameter × 12.0 to 13.0 cm long), and large (>4.5 cm diameter × >14 cm long) pickling cucumbers. Lesions developed on cucumbers incubated at all temperatures tested except 10 and 35°C. Disease severity was greatest on cucumbers incubated at 25°C at 4 days postinoculation (dpi). Lesions formed on cucumbers incubated at all relative humidities tested. The diameter of water-soaking and pathogen growth increased as the incubation relative humidity increased. Wounding lessened age-related resistance in pickling cucumbers. The diameter of water-soaking was similar for all wounded cucumbers at 4 dpi regardless of fruit size. Sporangial production was greater on small and medium fruits than on large fruits. These results indicate that P. capsici is capable of infecting cucumbers over a wide range of temperature and relative humidity conditions. Wounding increases the susceptibility of pickling cucumbers to P. capsici.

The Influence of Environmental Factors on Oryzalin Activity

Weed Science ◽  
1983 ◽  
Vol 31 (5) ◽  
pp. 752-758 ◽  
Author(s):  
James E. Nelson ◽  
William F. Meggitt ◽  
Donald Penner ◽  
James S. Ladlie
Keyword(s):  
Environmental Factors ◽  
Foxtail Millet ◽  
Grain Sorghum ◽  
Amaranthus Retroflexus ◽  
Surface Irrigation ◽  
Setaria Verticillata ◽  
Effects Of Temperature ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Smooth Pigweed

Effects of temperature, sunlight, soil incorporation and surface irrigation on the phytotoxicity of oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) were studied. The activity of oryzalin applied 4 to 6 weeks prior to planting was enhanced by covering the soil with plastic as measured by the inhibition of grain sorghum [Sorghum bicolor(L.) Moench. 'Sexauer G-701′] root growth. Growth chamber studies demonstrated that oryzalin phytotoxicity to grain sorghum was greater at 20 and 25 C than at 30C. The control of foxtail millet[Setaria italica(L.) Beauv. #5SETIT] bristly foxtail[Setaria verticillata(L.) Beauv. # SETVE], redroot pigweed (Amaranthus retroflexusL. # AMARE), and smooth pigweed (Amarantbus hybridusL.), and injury to grain sorghum increased as the thoroughness of mechanical incorporation of oryzalin into soil increased. The phytotoxicity of surface-applied oryzalin increased with increasing amounts of irrigation water until it equaled the level of a preplant-incorporated treatment.

Mineral Nutrition and the Parasite-Host Relationship of Witchweed

Weed Science ◽  
1971 ◽  
Vol 19 (5) ◽  
pp. 528-533 ◽  
Author(s):  
G. H. Egley
Keyword(s):  
Relative Humidity ◽  
Mineral Nutrition ◽  
Mineral Nutrients ◽  
High Relative Humidity ◽  
Nutrient Level ◽  
Sorghum Vulgare ◽  
Nutrient Levels ◽  
Chamber Studies ◽  
Growth Chamber Studies ◽  
Relationship Of

The influence of mineral nutrition on the parasite-host relationship of witchweed (Striga luteaLour.) and sorghum (Sorghum vulgarePers. ‘Texas Bighead’) was investigated in greenhouse and growth chamber studies. Sorghum was grown in Eustis loamy sand, either infested or not infested with witchweed, and treated with one of three levels of mineral nutrients. Witchweed reduced host-shoot yields by about 70% at the low nutrient levels and by about 45% at the highest nutrient level. Witchweed produced seed at all nutrient levels, whereas the host produced seed at the highest level only. Increased nutrition also increased witchweed yields. Regardless of nutrient level, an early attack by witchweed was more destructive to the host than a late attack. Growth of witchweed in soil also was studied after the parasite was detached from the host or the host shoot was removed. When only the host shoot was removed, (a) witchweed growth was inhibited; (b) feeding of sucrose to witchweed did not restore parasite growth; (c) mineral nutrients were toxic to the parasite; and (d) high relative humidity around witchweed protected it from the nutrient toxicity. High relative humidity enhanced survival of the detached parasite but markedly inhibited growth of witchweed in the intact parasite-host relationship.

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