MOVEMENT AND ACCUMULATION OF MERCURY IN APPLE TREES AND SOIL

1962 ◽  
Vol 42 (2) ◽  
pp. 280-285 ◽  
Author(s):  
R. G. Ross ◽  
D. K. R. Stewart

When sprays of Erad (phenyl mercury acetate) were applied to apple foliage the mercury moved in and from the foliage mainly by translocation rather than by volatilization. It moved to growing fruit and new foliage but there was no uptake through roots.Residues of mercury were found almost entirely in the top 2 inches of the soil in apple orchards sprayed with Erad.

1967 ◽  
Vol 47 (2) ◽  
pp. 169-174 ◽  
Author(s):  
D. K. R. Stewart ◽  
R. G. Ross

Mercury was readily translocated to growing fruit of apple trees which had received one cover spray of phenyl mercury acetate between June 14 and August 31. The rate of translocation was less with cover sprays applied near the end of this period. Translocation due to a phenyl mercury acetate cover spray occurred to about the same extent in the apple varieties McIntosh, Cortland, Red Delicious and Gravenstein. In addition to phenyl mercury acetate, a cover spray of phenyl mercury chloride, phenyl mercury dimethyl dithiocarbamate, phenyl mercury triethanol ammonium lactate, phenyl mercury monoethanol ammonium acetate, and mercuric chloride resulted in similar translocation of mercury to growing fruit.


1963 ◽  
Vol 43 (4) ◽  
pp. 497-502 ◽  
Author(s):  
R. G. Ross ◽  
R. P. Longley

A 4-year test was carried out on the effect of sprays of captan, dodine, dichlone, and phenyl mercury acetate-captan on the performance of mature McIntosh apple trees. Increases in yield of the same trees over the average yield of the previous 5 years were 40, 31, 18 and 7 per cent, respectively, for captan, dodine, mercury-captan and dichlone. The fungicides had little effect on bloom, tree growth as measured by increase in trunk cross-section, and per cent fruit color. Mercury-captan produced larger apples indicating a thinning effect. The captan sprays produced the most attractive apples. With dichlone, fruit finish was rough. Dodine injured about 3 per cent of the apples in 2 years of the test.Dodine gave the best control of apple scab (Venturia inaequalis). Dichlone was very effective for early fruit scab but did not give good control of late or pin-point scab. Mercury gave excellent control of early scab. Captan allowed some late scab to develop.


2015 ◽  
Vol 68 ◽  
pp. 250-256 ◽  
Author(s):  
N.T. Amponsah ◽  
M. Walter R.M. Beresford ◽  
R.W.A. Scheper

Leaf scar wounds are important sites for Neonectria ditissima infection of apple trees Monitoring leaf fall in Scilate/Envy and Braeburn trees to estimate leaf scar wound presence showed maximum leaf scar incidence occurred in June (early winter) Wounds detected in New Zealand apple orchards were bud scale scars fruit thinning and picking wounds leaf scars and pruning cuts Picking wounds are caused during harvest where the pedicel is detached from the shoot Susceptibility of these different types of wounds was determined using artificial inoculation of N ditissima conidia during the season Pruning cut wounds were the most susceptible followed by fruit picking and thinning wounds and the least susceptible were leaf scar wounds No infections were observed when bud scale wounds were inoculated There was no difference in wound susceptibility between cultivars but overall Scilate/Envy wounds developed more lesions than Braeburn wounds


2021 ◽  
Vol 13 (16) ◽  
pp. 3263
Author(s):  
Zhijie Liu ◽  
Pengju Guo ◽  
Heng Liu ◽  
Pan Fan ◽  
Pengzong Zeng ◽  
...  

The leaf area index (LAI) is a key parameter for describing the canopy structure of apple trees. This index is also employed in evaluating the amount of pesticide sprayed per unit volume of apple trees. Hence, numerous manual and automatic methods have been explored for LAI estimation. In this work, the leaf area indices for different types of apple trees are obtained in terms of multispectral remote-sensing data collected with an unmanned aerial vehicle (UAV), along with simultaneous measurements of apple orchards. The proposed approach was tested on apple trees of the “Fuji”, “Golden Delicious”, and “Ruixue” types, which were planted in the Apple Experimental Station of the Northwest Agriculture and Forestry University in Baishui County, Shaanxi Province, China. Five vegetation indices of strong correlation with the apple leaf area index were selected and used to train models of support vector regression (SVR) and gradient-boosting decision trees (GBDT) for predicting the leaf area index of apple trees. The best model was selected based on the metrics of the coefficient of determination (R2) and the root-mean-square error (RMSE). The experimental results showed that the gradient-boosting decision tree model achieved the best performance with an R2 of 0.846, an RMSE of 0.356, and a spatial efficiency (SPAEF) of 0.57. This demonstrates the feasibility of our approach for fast and accurate remote-sensing-based estimation of the leaf area index of apple trees.


1961 ◽  
Vol 41 (3) ◽  
pp. 499-502 ◽  
Author(s):  
R. G. Ross ◽  
S. A. Hamlin

Fifty isolates of Venturia inaequalis, from diseased apples of several varieties collected in sprayed orchards on various fungicide programs and in unsprayed orchards, were tested for their sensitivity to captan, glyodin, dichlone, phenyl mercury acetate, copper sulphate and sulphur. The isolates were sensitive to a wider dosage range of sulphur than of other fungicides but there was no indication that, in nature, V. inaequalis had developed strains resistant to the fungicides.


1962 ◽  
Vol 94 (11) ◽  
pp. 1187-1189 ◽  
Author(s):  
E. Fred Legner ◽  
Earl R. Oatman

Summer larvae of the eye-spotted bud moth, Spilonota ocellana (D. and S.), appeared in unequal densities on certain portions of apple trees in Door County, Wisconsin. The resulting non-random distribution introduced a bias in data obtained of the summer larvae. This phenomenon has been reported in Quebec apple orchards (LeRoux and Reimer, 1959) where densities of summer larvae were consistently greater in the upper than in the lower tree levels, and quadrant differences often occurred in the number of eggs parasitized, spring and summer larval shelters, and pupal shelters. The present study was initiated to determine the extent of the uneven distribution of summer eye-spotted bud moth larvae and nests on young, non-bearing apple trees. Summer larvae appear shortly after the first of August when eggs begin to hatch (Oatman, 1960).


1965 ◽  
Vol 45 (1) ◽  
pp. 86-89
Author(s):  
C. L. Lockhart ◽  
G. S. Swain

Chrysanthemum stool cuttings stored from November to May at 28°F to 34°F produced normal flowering plants when planted in the field. Rots seriously affected subsequent growth of stool cuttings stored at 37°F but not at 28°F to 34°F. When rots affected the growing tips only, weak lateral growth occurred on the stool cuttings. An Erad (phenyl mercury acetate) field spray before digging or Thylate as a dip or dust treatment after digging did not prevent mold or rot development in storage. Temperatures below 28°F injured stool cuttings.


1980 ◽  
Vol 112 (5) ◽  
pp. 527-528 ◽  
Author(s):  
J. P. McCaffrey ◽  
R. L. Horsburgh

The predaceous mirid Deraeocoris nebulosus (Uhler) is found on more than 50 species of ornamental trees and shrubs where it feeds on several important pest species (Wheeler et al. 1975). It is a common mite and aphid predator in commercial apple orchards in Virginia (Parrella et al. 1978). Wheeler et al. (1975) described the nymphal stages and biology, but made no mention of the egg or oviposition site. We describe the egg and oviposition site which we discovered while studying various predators of the European red mite, Panonychus ulmi (Koch), in Virginia apple orchards. Eggs and oviposition sites of other predaceous mirids associated with apple have been described (Kullenberg 1942; Collyer 1952, 1953; Sanford 1964; Horsburgh and Asquith 1968, 1970).


Plant Disease ◽  
2021 ◽  
Author(s):  
Shuwu Zhang ◽  
Jinhuan Chen ◽  
Lijun Ma ◽  
Enchen Li ◽  
Baoli Ji ◽  
...  

Wilting of branches and leaves was observed on 4-5 year old apple trees of the varieties Delicious and Fuji in orchards located in Wushan, Gansu Province, China in April 2018. Subsequently, the stem vascular tissue and woody xylem became discolored and necrotic. The stem dieback expanded rapidly to the entire vasculature of the branches. Finally, the epidermis of the stem bases split and was covered with light pink mold. For the pathogen isolation, 25 symptomatic stems were collected from 25 symptomatic trees in 3 individual orchards. Fragments (approximately 0.5 cm in length × 0.5 cm in width) of symptomatic stems were surface sterilized and individually transferred to Petri dishes containing potato dextrose agar (PDA), and incubated for 4 days at 25°C. Five types of isolates with distinct morphological characteristics (PJ1 to PJ5) were obtained from the 25 symptomatic stems after the single spore inoculation and sub-culture. The isolation frequency of PJ1, PJ2, PJ3, PJ4 and PJ5 types was 11%, 8%, 100%, 4% and 13%, respectively, in the 25 symptomatic stems. A spore suspension of PJ1, PJ2, PJ3, PJ4 and PJ5 types was prepared by adding 5 ml of sterile distilled water in the 14-day old culture colonies and filtered through 0.22 mm Millipore membranes, and the final concentration was adjusted to 108 per ml for inoculation. Detached healthy apple stems (15 cm in length) were surface-disinfested and used to evaluate the pathogenicity of PJ1 (7 isolates), PJ2 (5 isolates), PJ3 (32 isolates), PJ4 (2 isolates) and PJ5 (9 isolates) by dipping the stems into sterilised tubs containing the spore suspension (108 per ml) of each isolate. Apple stems dipped in sterile distilled water served as the control. Each control and treatment were repeated 3 times. At day 15 and 35, the stems infected with the spore suspension of PJ3 isolates developed symptoms that were similar to those observed in the apple orchards. However, the other four types (PJ1, PJ2, PJ4 and PJ5) exhibited either no symptoms or different symptoms from those observed in the apple orchards. There were no symptoms on the control stems. After the colony of the pathogen (PJ3 type) was re-isolated from the infected stem bases 35 days inoculation. The PJ3 type isolates with same morphological characteristics as the original PJ3 type isolates were used for further examination and identification. After 4 days of incubation on PDA, the colonies of PJ3 type isolates developed velvety aerial mycelia with white or light pink color when they were viewed from the front/top side of the PDA and orange-red color when they were viewed from the reverse/bottom side. After 14 days of incubation, the color in the centre of the colonies changed to yellow green in the front view and carmine red in the reverse view of the plates. Three types of spores (microconidia, macroconidia and chlamydospores) were observed after incubation of PJ3 type isolates for 14 days. The size (width and length) of 30 conidia in each of PJ3 type isolates was measured and averaged. The microconidia were abundant on aerial mycelia and limoniform, oval or pyriform with 0-1 septa. Their size ranged from 1.94 μm to 8.05 μm in length and 1.48 μm to 3.62 μm in width. The macroconidia were falciform and curved in shape, mostly with 3-5 septa and a size ranging from 13.52 μm to 22.43 μm in length and 2.31 μm to 3.87 μm in width. The chlamydospores were spherical, intercalary and formed in chains on PDA plates. These morphological characteristics indicate that the PJ3 type isolates could be Fusarium tricinctum (Chen et al. 2019; Aktaruzzaman et al. 2018). To confirm the morphological identification, the sequences of internal transcribed spacer (ITS), transcriptional enhancer factor-1 (TEF-lα) and ribosomal RNA large subunit gene (LSU) of the representative isolate PJ3-3 selected from the PJ3 type isolates with same morphological characteristics were sequenced and used for molecular identification (Laurence et al. 2011; Abd-Elsalam et al. 2003; Miller et al. 1996). The sequences of ITS, TEF-lα and LSU of the PJ3-3 isolate were deposited in NCBI database with the accession numbers of MZ799356, MZ820045 and MZ820044, respectively. In BLAST analyses, the obtained sequences of the PJ3-3 isolate showed 99.47%, 100% and 99.01% identity to the corresponding region of F. tricinctum ITS (JX179207.1: 3-566 Fusarium tricinctum isolate Fyx 1), TEF-lα (MK032320.1 F. tricinctum isolate ZD3) and LSU (KC311496.1 Fusarium tricinctum isolate L12), respectively. The phylogenetic analysis clustered the PJ3-3 isolate sequences within the same clade with ITS, TEF-lα and LSU sequences of F. tricinctum isolates. Thus, the PJ3-3 isolate was identified as F. tricinctum based on the pathogenicity tests, morphological characteristics and molecular analyses. Previously, the symptoms of xylem browning and dieback were observed in the twigs of wild apple trees that were collected from wild apple forests, and the species F. avenaceum, F. solani, F. tricinctum, F. proliferatum, and F. sporotrichioides were isolated from diseased wild apple trees (Chen et al. 2019). Only F. avenaceum, F. solani, F. proliferatum, and F. sporotrichioides were reported as the pathogens causing the disease symptoms of xylem browning and dieback in wild apple trees in Xinjiang, China (Chen et al. 2019). In our present study, we found that F. tricinctum can cause stem vascular and woody xylem browning, wilting, and dieback in the apple tree varieties Delicious and Fuji. These are new symptoms discovered in our present research and different from the previous paper (Chen et al. 2019). Therefore, to our knowledge, this study is the first report of F. tricinctum causing a new disease on apple trees in China following Koch’s postulates. Our findings are important for the management of apple disease and protect apple trees in the future.


2021 ◽  
Vol 10 (50) ◽  
Author(s):  
A. M. Jimenez Madrid ◽  
T. Klass ◽  
V. Roman-Reyna ◽  
J. Jacobs ◽  
M. L. Lewis Ivey

Erwinia amylovora is the causative agent of fire blight, a devastating disease of apples and pears worldwide. Here, we report draft genome sequences of four streptomycin-sensitive strains of E. amylovora that were isolated from diseased apple trees in Ohio.


Sign in / Sign up

Export Citation Format

Share Document