Percentage of Curly Leaf Infection in Beet Leafhopper (Eutettix Tenella Baker) and Winter Host Plants under Field Conditions

1925 ◽  
Vol 18 (5) ◽  
pp. 733-737 ◽  
Author(s):  
Henry H. P Severin
Keyword(s):  
Host Plants ◽  
Field Conditions ◽  
Beet Leafhopper ◽  
Leaf Infection ◽  
Curly Leaf

Susceptibility of subterranean clover varieties to powdery mildew under controlled environment and field conditions

1991 ◽  
Vol 31 (1) ◽  
pp. 81 ◽  
Author(s):  
MJ Barbetti ◽  
PGH Nichols
Keyword(s):  
Powdery Mildew ◽  
Subterranean Clover ◽  
Field Conditions ◽  
Controlled Environment ◽  
Excellent Correlation ◽  
Good Resistance ◽  
Breeding Programs ◽  
Leaf Infection ◽  
High Degree ◽  
Field Plots

Thirty-three subterranean clover varieties, comprising 16 commercial cultivars and 17 promising midseason breeding and introduced lines, were screened for resistance to powdery mildew (caused by Erysiphe polygonii) under controlled environment conditions, and where possible, comparisons were made with their performance in field plots. There were large differences between varieties in the incidence and severity of powdery mildew on plants. Under controlled environment conditions, Tallarook, CPI 47308C, CPI 89860D, 75S13-12, CPI 6.53284 CPI 89820D and Clare had the lowest levels of leaf infection, the lowest mildew sporulation scores and the least amount of leaf scorching from mildew infection. Karridale had the highest level of leaf infection, followed by 69837-1, 76841-1, Junee, Bacchus Marsh and 69S37-3. Under field conditions, Tallarook, CPI 47308C, CPI 65328A and CPI 65328F were mildew-free, while CPI 89777C, CPI 89860D, CPI 89830F, CPI 89841E, Clare and Rosedale had good resistance. Junee was clearly the most susceptible under field conditions, followed by 76S41-1, 69837-3, Karridale, Bacchus Marsh and 69S37-1. There was generally excellent correlation between the different powdery mildew disease parameters, namely leaf infection, mildew sporulation and leaf scorch, measured under controlled environment conditions, and there was also good overall correlation between controlled environment and field data. Bacchus Marsh, Junee, 69337-1, 69837-3 and 76341-1 were highly susceptible under both controlled environment and field conditions, indicating that either environment could be used to identify highly susceptible varieties. Under controlled environment conditions, a high degree of resistance was observed in Clare, CPI 47308C, CPI 65328A, CPI 89820D, CPI 89860D and 75S13-12, while field plots of the varieties Tallarook, CPI 47308C and CPI 65328A showed a complete absence of powdery mildew. These varieties may have value as parents in breeding programs for powdery mildew resistance.

scholarly journals Host Range of Oidium lycopersicum on Selected Solanaceous Species in Connecticut

Plant Disease ◽  
1999 ◽  
Vol 83 (4) ◽  
pp. 341-344 ◽  
Author(s):  
J. A. LaMondia ◽  
V. L. Smith ◽  
S. M. Douglas
Keyword(s):  
Powdery Mildew ◽  
Field Conditions ◽  
Breeding Line ◽  
Breeding Lines ◽  
Eastern Black Nightshade ◽  
Black Nightshade ◽  
Leaf Infection ◽  
Tomato Cultivars ◽  
Tomato Breeding ◽  
Oidium Lycopersicum

Powdery mildew of tomato in Connecticut was identified as Oidium lycopersicum based on anamorph characteristics. On tomato, conidia were most often formed singly or in pairs on unbranched conidiophores. Mycelium was hyaline and measured 5 to 7 μm. Cleistothecia were not found. This fungus caused disease on a number of tomato cultivars ranging in size from seedlings to mature plants under greenhouse and field conditions. Eastern black nightshade, eggplant, tobacco, and potato were infected in the greenhouse. Reciprocal inoculation experiments between tomato and nightshade and eggplant and tobacco demonstrated cross-infectivity, but the size and number of conidia per conidiophore varied between hosts. Conidia from tobacco, eggplant, and nightshade averaged 37.8 by 19.1 μm (SE = 0.5 and 0.2, respectively) with a 95% confidence interval (CI) of 35.5 to 40.0 by 18.1 to 20.3 μm (n = 300). Conidia from tomato were smaller, averaging 33.6 by 18.2 μm (SE = 0.3 and 0.2, respectively) with a 95% CI of 32.7 to 34.4 by 17.5 to 18.9 μm (n = 300). Conidia from potato averaged 32.4 by 16.6 μm (SE = 0.4 and 0.2, respectively) with a 95% CI of 31.5 to 33.3 by 16.3 to 17.0 μm (n = 100). There were significant differences in percent leaf infection and powdery mildew disease ratings between Lycopersicon esculentum cultivars and Lycopersicon breeding lines under both greenhouse and field conditions. Most commercial tomato cultivars were severely affected by powdery mildew. Cultivars such as Rutgers were not as extensively colonized by O. lycopersicum, compared to cultivars such as Celebrity and Nema 1200, but the severity of powdery mildew was still quite high. L. hirsutum and the tomato breeding line Hirol 3-21 were the only plants tested that were resistant to O. lycopersicum.

Susceptibility of subterranean clover varieties to rust under controlled environment and field conditions

1991 ◽  
Vol 31 (1) ◽  
pp. 77 ◽  
Author(s):  
MJ Barbetti ◽  
PGH Nichols
Keyword(s):  
Rust Resistance ◽  
Subterranean Clover ◽  
Field Conditions ◽  
Controlled Environment ◽  
Good Resistance ◽  
Breeding Programs ◽  
Commercial Cultivars ◽  
Leaf Infection ◽  
High Degree ◽  
Field Plots

Thirty-two subterranean clover varieties, comprising 17 commercial cultivars, 1 named variety and 14 promising midseason breeding and introduced lines, were screened for resistance to rust (caused by Uromyces trifolii-repentis) under controlled environment conditions, and where possible, comparisons were made with their performance in field plots. There were large differences between varieties in the incidence and severity of rust on plants. Under controlled environment conditions, cvv. Gingin, Meteora and Enfield, and to a lesser extent Larisa and Trikkala, had the lowest levels of rust leaf infection, the lowest rust pustule densities and the smallest rust pustules. Seaton Park had a relatively low pustule density and CPI 89830F had relatively small pustules. Gingin and Enfield had the least leaf collapse. Green Range was the most susceptible under controlled environment conditions, followed by Bacchus Marsh, Karridale, CPI 47308C and CPI 89841E. Under field conditions, Enfield, Meteora, Trikkala and CPI 89822H were rust free, while Larisa, CPI 47308C, CPI 65328F, 75S13-12, 76841-1, CPI 89830F and CPI 89880J had good resistance. Green Range was clearly the most susceptible under field conditions, followed by Seaton Park, Karridale, Bacchus Marsh, CPI 89774F and CPI 89841E. While there was often good correlation between the field and controlled environment data for the different parameters, the resistance rankings of some varieties varied widely, depending upon whether screened under controlled environment or field conditions. Green Range, Karridale, Seaton Park and CPI 89841E were highly susceptible to rust under both controlled and field conditions, indicating that either environment could be successfully used to identify highly susceptible varieties. The high degree of resistance observed in Enfield, Gingin and Meteora, and to a lesser extent in Larisa and Trikkala, suggests their value as parents in breeding programs for rust resistance.

The role of pycnidiospores of Leptosphaeria maculans in the spread of blackleg disease in rape

1976 ◽  
Vol 16 (83) ◽  
pp. 911 ◽  
Author(s):  
MJ Barbetti
Keyword(s):  
Brassica Napus ◽  
Leptosphaeria Maculans ◽  
Field Conditions ◽  
Disease Spread ◽  
Blackleg Disease ◽  
Leaf Infection ◽  
Infection Spread

The development and spread of blackleg leaf, stem and crown infections in rape plants (Brassica napus cv. Zephyr), caused by Leptosphaeria maculans pycnidiospores, was examined under field conditions for plants artificially inoculated at 3, 5 1/2 and 8 1/2 weeks of age. Spread of leaf, stem and crown infections, via pycnidiospores, occurred for inoculations made on 3- and 5 1/2-week-old plants. Inoculation at three weeks oflage resulted in theigreatest disease spread. There was no leaf infection spread and very little stem and crown infection spread for the inoculation made on the 8 1/2-week-old plants.

Development and Survival of the Onion Maggot under Field and Artificial Conditions on Attractive and Unattractive Onion Varieties

1963 ◽  
Vol 95 (3) ◽  
pp. 334-336 ◽  
Author(s):  
J. P. Perron ◽  
J. J. Jasmin
Keyword(s):  
Larval Development ◽  
Allium Cepa ◽  
Host Plants ◽  
Nutritive Value ◽  
Field Conditions ◽  
Allium Fistulosum ◽  
Onion Maggot ◽  
Hylemya Antiqua ◽  
Larval Stages ◽  
Petri Dishes

AbstractWhen onions were grown in cages under field conditions, the number of plants killed per egg deposited by hand showed no significant differences between any of the varieties studied, indicating that onion maggot (Hylemya antiqua (Meig.)) fed, developed, and survived as well on varieties Nebuka and Hishiko (Allium fistulosum L.) as on White Globe Southport (Allium cepa L.) and Beltsville Bunching (A. cepa × A. fistulosum), even though the last two varieties were more attractive for natural oviposition in the field. When larvae were fed in petri dishes with crushed tissues of onion plants, no significant differences were obtained between any of the varieties in the duration of larval stages, number of pupae, weight of pupae, or number of adults, whereas in glass vials, a better larval development, a higher number of heavier pupae, and a higher number of adults were obtained from the unattractive varieties. Therefore, it appears that the preference of the females to lay eggs in the field on varieties White Globe South-port and Beltsville Bunching is not associated with the nutritive value of the host-plants.

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