scholarly journals Predator or plant pest? Observations on Parascolothrips priesneri Mound (Thysanoptera: Thripidae) in Israeli apple orchards

2016 ◽  
Vol 48 (1) ◽  
pp. 37
Author(s):  
T. Ben-David ◽  
L.A. Mound
Keyword(s):  
Apple Orchards ◽  
Feeding Damage ◽  
Apple Trees ◽  
Plant Pest

Field and laboratory observations on <em>Parascolothrips priesneri</em> failed to confirm previous reports that this insect is a predator of mites, but instead demonstrated that it can cause severe feeding damage to the leaves of apple trees.

Seasonal wound presence and susceptibility to Neonectria ditissima infection in New Zealand apple trees

2015 ◽  
Vol 68 ◽  
pp. 250-256 ◽  
Author(s):  
N.T. Amponsah ◽  
M. Walter R.M. Beresford ◽  
R.W.A. Scheper
Keyword(s):  
New Zealand ◽  
Artificial Inoculation ◽  
Early Winter ◽  
Leaf Fall ◽  
Apple Orchards ◽  
Apple Trees ◽  
Leaf Scar ◽  
Fruit Thinning ◽  
Different Types

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

scholarly journals Gradient Boosting Estimation of the Leaf Area Index of Apple Orchards in UAV Remote Sensing

2021 ◽  
Vol 13 (16) ◽  
pp. 3263
Author(s):  
Zhijie Liu ◽  
Pengju Guo ◽  
Heng Liu ◽  
Pan Fan ◽  
Pengzong Zeng ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Shaanxi Province ◽  
Gradient Boosting ◽  
Support Vector ◽  
Apple Orchards ◽  
Apple Trees ◽  
Area Index ◽  
Spatial Efficiency

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.

Sampling and Distribution of Summer Eye-spotted Bud Moth Spilonota ocellana (D. & S.), Larvae and Nests on Apple Trees

1962 ◽  
Vol 94 (11) ◽  
pp. 1187-1189 ◽  
Author(s):  
E. Fred Legner ◽  
Earl R. Oatman
Keyword(s):  
Random Distribution ◽  
Uneven Distribution ◽  
Apple Orchards ◽  
Apple Trees

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).

THE EGG AND OVIPOSITION SITE OF DERAEOCORIS NEBULOSUS (HEMIPTERA: MIRIDAE) ON APPLE TREES

1980 ◽  
Vol 112 (5) ◽  
pp. 527-528 ◽  
Author(s):  
J. P. McCaffrey ◽  
R. L. Horsburgh
Keyword(s):  
Panonychus Ulmi ◽  
Oviposition Site ◽  
Pest Species ◽  
Apple Orchards ◽  
Apple Trees ◽  
European Red Mite ◽  
Important Pest ◽  
Ornamental Trees ◽  
Trees And Shrubs ◽  
Oviposition Sites

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).

scholarly journals First report of a new disease caused by Fusarium tricinctum on apple tree in China

Plant Disease ◽  
2021 ◽  
Author(s):  
Shuwu Zhang ◽  
Jinhuan Chen ◽  
Lijun Ma ◽  
Enchen Li ◽  
Baoli Ji ◽  
...  
Keyword(s):  
Apple Tree ◽  
Morphological Characteristics ◽  
Spore Suspension ◽  
Morphological Identification ◽  
Distilled Water ◽  
New Disease ◽  
Apple Orchards ◽  
Apple Trees ◽  
First Report ◽  
Fusarium Tricinctum

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.

scholarly journals Draft Genome Sequences of Four Streptomycin-Sensitive Erwinia amylovora Strains Isolated from Commercial Apple Orchards in Ohio

2021 ◽  
Vol 10 (50) ◽  
Author(s):  
A. M. Jimenez Madrid ◽  
T. Klass ◽  
V. Roman-Reyna ◽  
J. Jacobs ◽  
M. L. Lewis Ivey
Keyword(s):  
Causative Agent ◽  
Fire Blight ◽  
Erwinia Amylovora ◽  
Draft Genome ◽  
Apple Orchards ◽  
Genome Sequences ◽  
Apple Trees ◽  
Content Type

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.

scholarly journals Distribution of Apple stem grooving virus in apple trees in the Czech Republic

2001 ◽  
Vol 37 (No. 1) ◽  
pp. 1-4 ◽  
Author(s):  
J. Polák ◽  
J. Zieglerová
Keyword(s):  
Czech Republic ◽  
Health Condition ◽  
Apple Orchards ◽  
Apple Trees ◽  
The Czech Republic ◽  
Apple Stem Grooving Virus ◽  
Apple Stem ◽  
High Incidence

From 1997 to 2000 the distribution of Apple stem grooving virus (ASGV) in selected intensive apple orchards was investigated at six sites in the Czech Republic. Detection of ASGV was by ELISA. The virus was found to be commonly distributed; it was detected in over 50 % of the tested trees. Some cultivars were infected up to 100 %, while several were found to be virus-free. A high incidence of infected trees appeared in both older (20 years) and younger (7 to 8 years) orchards. This emphasizes the necessity to initiate the certification of the health condition of nursery material according to the system recommended by the EPPO.

The Influence of Spray Programs on the Fauna of Apple Orchards in Nova Scotia. VII. Effects on Some Beneficial Arthropods

1954 ◽  
Vol 86 (3) ◽  
pp. 128-135 ◽  
Author(s):  
A. W. MacPhee ◽  
K. H. Sanford
Keyword(s):  
Nova Scotia ◽  
Natural Enemies ◽  
Apple Orchards ◽  
Beneficial Arthropods ◽  
Population Densities ◽  
Apple Trees ◽  
Arthropod Pests

The toxicities of a large number of spray chemicals to arthropod pests are well known. In most instances, observations on the effects of such materials on natural enemies have beeen incidental to other studies, and little has been published on experiments designed to determine the direct toxicities of the chemicals to beneficial species. The effects of spray chemicals on the predators and parasites of the major pests of apple trees in Nova Scotia have been investigated as part of a broader project on the factors that influence population densities of orchard arthropods, as outlined by Pickett et al. (31).

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