scholarly journals A modified leaf disk method for rearing predaceous mites [Acarina : Phytoseiidae]

2005 ◽  
Vol 73 (2) ◽  
pp. 69-72 ◽  
Author(s):  
J. Brodeur ◽  
C. Cloutier
Keyword(s):  
Nutrient Solution ◽  
Retention Time ◽  
Frankliniella Occidentalis ◽  
Leaf Disk ◽  
Cotton Wool ◽  
Detached Leaf ◽  
Predaceous Mites ◽  
Predaceous Mite ◽  
Disk Method ◽  
Leaf Disks

The detached leaf disk method for rearing phytoseiids was modified by maintaining leaf disks on a nutrient solution solidified with agar. The predaceous mite, Amblyseius cucumeris, and thrips prey, Frankliniella occidentalis, were successfully reared on cucumber leaf disks using this technique. Predator survival and retention time on agar as the leaf supporting medium were improved compared to cotton wool. Agar prolonged leaf disk quality for thrips survival compared to both cotton wool and water, while offering other significant advantages to these alternative media.

Studies on rates of development and reproduction of California red scale, Aonidiella aurantii (Mask.) (Homoptera : Diaspididae) on citrus

1972 ◽  
Vol 20 (1) ◽  
pp. 37 ◽  
Author(s):  
JR Willard
Keyword(s):  
Leaf Disk ◽  
Distilled Water ◽  
Aonidiella Aurantii ◽  
Innate Capacity ◽  
Disk Method ◽  
Capacity For Increase

Red scale were reared in the laboratory on disks cut from lemon leaves floated on distilled water in plastic vials. Scales could be reared to maturity on the disks and females would produce crawlers. Rates of development measured at four temperatures using the leaf disk method were similar to data reported by earlier authors. Unfertilized females were found to remain alive and could be fertilized up to 16 weeks after the second moult. On the average, the longevity of unfertilized females was shown to be 3.5 weeks longer than that of fertilized females. The fecundity of females collected from the field was measured at a series of constant temperatures. Estimates of the capacity for increase (rc) and the innate capacity for increase (rm were obtained at four temperatures. Both these statistics were shown to be greatly influenced by temperature; rc was found to be an underestimate of rm at higher temperatures.

scholarly journals Sensitivity of Uncinula necator to Benomyl, Triadimefon, Myclobutanil, and Fenarimol in California

Plant Disease ◽  
1997 ◽  
Vol 81 (3) ◽  
pp. 293-297 ◽  
Author(s):  
H. L. Ypema ◽  
M. Ypema ◽  
W. D. Gubler
Keyword(s):  
Leaf Disk ◽  
Cross Resistance ◽  
Uncinula Necator ◽  
Development Of Resistance ◽  
Pairwise Correlations ◽  
Dmi Fungicides ◽  
Leaf Disks

Sensitivity of Uncinula necator subcultures to benomyl and the demethylation-inhibiting (DMI) fungicides triadimefon, myclobutanil, and fenarimol was assessed in 1993, 1994, and 1995 with leaf disk bioassays. In 1993, 1994, and 1995, 81.8, 96, and 96.7% of the subcultures, respectively, did not grow on leaf disks treated with 30 mg of benomyl per liter, whereas growth of the remaining subcultures was inhibited by more than 90%. Median EC50 values of triadimefon, myclobutanil, and fenarimol decreased from 1993 to 1994, and those of triadimefon decreased again from 1994 to 1995. In the same period, median EC50 values of all three DMI fungicides increased in a vineyard never exposed to DMI fungicides. The highest means and ranges of EC50 values found were those of triadimefon. Means and ranges were lower for myclobutanil and lowest for fenarimol, reflecting differences in inherent activities of the fungicides and po-tential for development of resistance. Pairwise correlations between EC50 values of each DMI fungicide were positive and confirmed earlier indications of cross resistance.

scholarly journals Influence of Dew Period and Temperature on Foliar Infection of Greenhouse-Grown Tomato by Colletotrichum coccodes

Plant Disease ◽  
1998 ◽  
Vol 82 (6) ◽  
pp. 639-641 ◽  
Author(s):  
J. M. Byrne ◽  
M. K. Hausbeck ◽  
C. Meloche ◽  
A. M. Jarosz
Keyword(s):  
Leaf Disk ◽  
Leaf Wetness ◽  
Colletotrichum Coccodes ◽  
Leaf Position ◽  
Leaf Wetness Duration ◽  
The Mean ◽  
Effects Of Temperature ◽  
Leaf Disks

Effects of temperature, duration of leaf wetness, and leaf position on foliar infection of greenhouse-grown tomato (cv. Bonnie Best) by Colletotrichum coccodes were determined by inoculating plants with C. coccodes (5.0 × 105 conidia per ml) and keeping them in a dew chamber for 0, 4, 8, 12, 16, 20, or 24 h of wetting at 15, 20, or 25°C. One week after inoculation, leaf disks were placed on the surface of an amended medium on which colonies of C. coccodes were compact and easily identified, and severity of infection was quantified after 4, 6, and 8 days. There was no infection of plants incubated at 15°C, while plants kept at 20 or 25°C had increasing numbers of colonies when leaf wetness duration was extended beyond 12 and 8 h, respectively. Leaf position had a significant effect, with leaves tending to increase in susceptibility as they age. After 24 h of leaf wetness at 25°C, the mean number of colonies per leaf disk from top, middle, and bottom leaves was 23.8, 29.0, and 34.0, respectively.

scholarly journals Direct induction of adventitious root in Schefflera octophylla (Lour.) Harms from leaf explants cultured in vitro

2021 ◽  
Vol 19 (3) ◽  
pp. 495-507
Author(s):  
Huynh Thi Luy ◽  
Nguyen Huu Ho ◽  
Bui Van Le
Keyword(s):  
Plant Species ◽  
Adventitious Root ◽  
High Efficiency ◽  
Light Condition ◽  
Leaf Explants ◽  
Leaf Disk ◽  
Root Number ◽  
Direct Formation ◽  
Leaf Disks

Schefflera octophylla (Lour.) Harms is a precious plant species belonging to the Araliaceae family. All parts of plant have been used to create products for human health. In tissue culture of medicinal plants, the induction and multiplication of adventitious root of Schefflera octophylla for biomass collection have been studied. In this report, results on induction of adventitious root from leaf explants cultured in vitro of this plant species were presented. Leaf disks (~ 10 x 10 mm), leaf transverse - thin cell layers (t-TCLs) (~ 3 x 10 mm) were cultured on different mineral media MS, ½MS, B5, SH with NAA (0 - 5 mg/L), sucrose (0 - 50 g/L) and light intensity (0 - 4,000 lux). The results showed that, 30 days after culturing on ½MS solid medium plus 3 mg/L NAA, and 30 g/L sucrose in 4,000 lux light condition, direct formation of adventitious root was best from leaf disks, t-TCLs with rooting rate (%) 100, 100; root number/sample 68.80, 21.96; root lenght (mm) 16.53, 15.53, respectively. Leaf disk culture resulted in better rooting than t-TCL culture in two criteria of root number and root length. Morphological and histological observations of adventitious root primordia formation in the leaf disk were also performed. This is the first report on direct formation of adventitious root by in vitro culture of leaf disks/t-TCLs in Schefflera octophylla with very high efficiency, creating basis for further studies on root biomass multiplication for production of bioactive compounds.  

scholarly journals Genome-Wide Associations with Resistance to Bipolaris Leaf Spot (Bipolaris oryzae (Breda de Haan) Shoemaker) in a Northern Switchgrass Population (Panicum virgatum L.)

2018 ◽  
Author(s):  
Kittikun Songsomboon ◽  
Ryan Crawford ◽  
Jamie Crawford ◽  
Julie Hansen ◽  
Jaime Cummings ◽  
...  
Keyword(s):  
Image Analysis ◽  
Resistance Genes ◽  
Leaf Spot ◽  
Panicum Virgatum ◽  
Leaf Disk ◽  
Phenotypic Variance ◽  
Bipolaris Oryzae ◽  
Association Panel ◽  
Detached Leaf ◽  
Genome Wide

ABSTRACTSwitchgrass (Panicum virgatum L.), a northern native perennial grass, suffers from yield reduction from Bipolaris leaf spot caused by Bipolaris oryzae (Breda de Haan) Shoe-maker. This study aimed for determining the resistant populations via multiple phenotyping approaches and identifying potential resistance genes to the disease from genome-wide association studies in the switchgrass northern association panel. The disease resistance was evaluated from both natural (field evaluations in NY and PA) and artificial inoculations (detached leaf and leaf disk assays). There are ten out of the 66 populations showed the most resistant based on a combination of detached leaf, leaf disk, and mean from two locations. The GWAS from five subgroups from the association panel to different disease evaluation combinations yielded 27 significant SNPs on 12 chromosomes: 1K, 2K, 2N, 3K, 3N, 4N, 5K, 5N, 6N, 7K, 7N, and 9N accumulatively explaining phenotypic variance of BLUPs of detached leaf percent lesion via image analysis 26.52% at most and BLUPs of leaf disk percent lesion via image analysis 3.28% at least. Within linkage disequilibrium of 20 kb, these SNP markers linked with the potential resistance genes including genes encoding for NBS-LRR, PPR, cell wall related proteins, homeostatic proteins, anti-apoptotic proteins, and ABC transporters.

Application of the leaf-disk method to the determination of photosynthesis in cereals

1961 ◽  
Vol 3 (3) ◽  
pp. 245-251 ◽  
Author(s):  
Lubomír Nátr ◽  
Josef Špidla
Keyword(s):  
Leaf Disk ◽  
Disk Method

Prediction of poplar leaf rust epidemics from a leaf-disk assay

1994 ◽  
Vol 24 (10) ◽  
pp. 2085-2088 ◽  
Author(s):  
Richard C. Hamelin ◽  
Richard S. Ferriss ◽  
Louis Shain ◽  
Bart A. Thielges
Keyword(s):  
Leaf Rust ◽  
Field Tests ◽  
Leaf Disk ◽  
Relative Area ◽  
Progress Curve ◽  
Intermediate Resistance ◽  
Poplar Leaf ◽  
Parent Ratio ◽  
Poplar Leaf Rust ◽  
Leaf Disks

The reliability of a leaf-disk assay to assess resistance of Populusdeltoides Bartr. to Melampsoramedusae Thuëm. f.sp. deltoidae, the causal agent of poplar leaf rust, was evaluated. Leaf disks of eight host genotypes were inoculated in a spore settling tower with 11 isolates of the pathogen in all possible combinations, and the latent period, infection probability, sporulation, and progeny/parent ratio were recorded. Correlations were established between these measures and measures derived from field epidemics, namely the relative area under the disease progress curve, the apparent rate of infection, the final disease severity, and the number of days before defoliation. Four genotypes were highly resistant to all 11 isolates tested with the leaf-disk assay and to the local inoculum in field tests. Three genotypes were highly susceptible in inoculation assays and were also susceptible in the field. One genotype was highly resistant in inoculation assays but had intermediate resistance in the field. Significant correlations (p < 0.05) were found between all leaf-disk and all field parameters.

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