Competition between Two Species of Mites. I. Experimental Results

1962 ◽  
Vol 94 (4) ◽  
pp. 365-375 ◽  
Author(s):  
W. H. Foott
Keyword(s):  
Ground Cover ◽  
Early Summer ◽  
Apple Orchard ◽  
Panonychus Ulmi ◽  
Residual Effects ◽  
Research Station ◽  
Large Numbers ◽  
Mite Control ◽  
Two Spotted Spider Mite ◽  
Peach Trees

Two principal pests of apple and peach trees in southwestern Ontario are the European red mite, Panonychus ulmi (Koch), and the two-spotted spider mite, Tetranychus telarius (L.). Usually only P. ulmi is present on the trees in large numbers during the spring and early summer, at which time T. telarius lives predominantly on the ground cover. In August, many T. telarius move from the ground cover to the trees, and large numbers of both species may then be present. In mite control investigations in an apple orchard at the Harrow Research Station, T. telarius moved onto the trees, especially in the central plots, regardless of the acaricides previously applied or the numbers of P. ulmi that were or had been present. This phenomenon posed the question of whether the residual effects of acaricides applied to the trees were mainly responsible for the size of P. ulmi populations in the central plots, or whether competition resulting from the ingress of T. telarius was partially responsible.

scholarly journals COMPETITIVE VEGETATIVE ORCHARD COVERS REDUCE PEACH ROOTING

HortScience ◽  
1992 ◽  
Vol 27 (6) ◽  
pp. 589g-589
Author(s):  
Michael L. Parker ◽  
John R. Meyer
Keyword(s):  
North Carolina ◽  
Tree Growth ◽  
Root Distribution ◽  
Sandy Loam ◽  
Ground Cover ◽  
Management Systems ◽  
Research Station ◽  
Root Numbers ◽  
Orchard Floor Management ◽  
Peach Trees

Peach trees (`Biscoe'/Lovell) were planted in March, 1988 in ten different ground cover management systems. The trees were planted at the Sandhills Research Station in Southeastern North Carolina on a Candor sand and Eunola sandy loam. In December, 1991 the trench profile method was used to evaluate root distribution under the six orchard floor management systems of nimblewill, bare ground control, centipedegrass, brome, bahiagrass, and weedy control. Trenches were dug parallel to the tree row 60 cm from the center of the row on both sides of the tree. Grids 1 meter square, sectioned into 10 cm squares, were placed on the profile walls and root distribution (in three size categories) was recorded for 1 meter on each side of the tree in each trench. Root numbers were greatly reduced under the vegetative covers that provided the greatest suppression of vegetative tree growth. Total root densities under the trees in the vegetative covers were ranked into three size categories which were correlated with the amount of vegetative tree growth.

A survey of the Arthropod fauna of plum trees at East Malling in 1966

1969 ◽  
Vol 58 (3) ◽  
pp. 581-599 ◽  
Author(s):  
Lena K. Ward
Keyword(s):  
Fungal Spores ◽  
Early Summer ◽  
Panonychus Ulmi ◽  
Leaf Damage ◽  
Research Station ◽  
Predacious Mites ◽  
Phytoseiid Mites ◽  
Predatory Bugs ◽  
Two Peaks ◽  
Different Parts

In an investigation of the fauna of plum at East Mailing Research Station in 1966, over 70 species of the commoner arthropods were listed.Different species of mite were found to prefer different parts of the tree, different parts of the leaf, and leaves of different ages on a shoot. Aculus fockeui (Nal. & Trt.) (Eriophyidae) was found to spread up the shoots during the early summer and to attain a density of over 100 per sq. cm. of leaf surface. Panonychus ulmi (Koch) was found to be commoner to the east of the tree, and leaf damage that it caused graded in severity across the plot. The species composition of populations of the Phytoseiid mites could differ markedly between trees in the same plot.A study of the population trends of the commoner species based on numbers per shoot revealed that the populations of aphids and their predators developed two peaks during the season. There was a relatively high incidence of Entomophthora infection on the aphids, and overwintering fungal spores were produced when the aphids died in crevices on the bark, but only short-lived cornidia when they died on the leaves. The population density of member species of the fauna varied considerably, the smallest phytophagous mites reaching levels of 200 per shoot, predacious mites 10.0 per shoot and predatory bugs such as Blepharidopterus angulatus (Fall.) only about 0.01 per shoot.

A STRAIN OF TETRANYCHUS URTICAE FROM THE GROUND COVER OF AN APPLE ORCHARD RESISTANT TO CHLORFENSON

1965 ◽  
Vol 45 (3) ◽  
pp. 226-228
Author(s):  
W. H. Foott
Keyword(s):  
Tetranychus Urticae ◽  
Ground Cover ◽  
Apple Orchard ◽  
Panonychus Ulmi ◽  
Spray Drift ◽  
Apple Trees ◽  
Low Level ◽  
Tetranychus Urticae Koch

A strain of Tetranychus urticae Koch (Acarina:Tetranychidae) developed a low level of resistance to chlorfenson when the material drifted to the ground cover while apple trees were sprayed for control of Panonychus ulmi (Koch). After being reared in the greenhouse for 4 years without further exposure to chlorfenson T. urticae lost its resistance. When Kelthane was substituted for chlorfenson as a control for P. ulmi the spray drift that reached the ground cover virtually eliminated T. urticae from the orchard.

Dispersal of the sugar-cane scale Aulacaspis tegalensis (Zhnt.) (Hem., Diaspididae) by air currents

1972 ◽  
Vol 61 (3) ◽  
pp. 547-558 ◽  
Author(s):  
D. J. Greathead
Keyword(s):  
Sugar Cane ◽  
Laboratory Experiments ◽  
Sticky Trap ◽  
Research Station ◽  
High Humidity ◽  
Dispersal Mechanism ◽  
Large Numbers ◽  
Speed Up ◽  
Trap Catches ◽  
Aulacaspis Tegalensis

By means of sticky traps and a suction trap, it was demonstrated on a plot of sugar-cane at Kawanda Research Station, Uganda, that large numbers of crawlers of Aulacaspis tegalensis (Zhnt.) become airborne (up to 10/m3). The numbers increase with wind speed up to about 2·0 m/s and then remain constant, but are depressed by increasing humidity. In laboratory experiments, crawler survival was reduced by high temperatures (30°C) and low humidities (30% r.h.), but some individuals should survive the extreme conditions sometimes experienced if airborne from morning until evening. On hatching, crawlers move upwards and towards the light, but downwards in the dark; movement is inhibited by high humidity. These behaviour responses indicate hat the presence of crawlers in the air is not accidental but a dispersal mechanism. At Arusha Chini, an isolated sugar estate in Tanzania, sticky-trap catches downwind of a windbreak confirmed that airborne dispersal of crawlers is a major source of infestation. It is shown that air currents could have carried crawlers to Arusha Chini from a source on the Kenya coast, 260 km to the east.

scholarly journals 29 Demonstrating the Effects of Deworming and Implanting Weaned Calves for Retained Ownership on Pasture in Eastern Oklahoma

2020 ◽  
Vol 98 (Supplement_2) ◽  
pp. 6-6
Author(s):  
Paul A Beck ◽  
Earl Ward ◽  
Scott Clawson ◽  
Brian Pugh ◽  
Rodney Farris
Keyword(s):  
Performance Enhancement ◽  
Animal Health ◽  
Economic Benefits ◽  
Early Summer ◽  
Research Station ◽  
Mixed Grass ◽  
Main Plot ◽  
Growth Promoting ◽  
Retained Ownership ◽  
Implant Treatment

Abstract The majority of cow-calf producers in Oklahoma sell their calves at weaning. Preconditioning and retained ownership through the stocker phase provides economic benefits to these operations. The objectives of this demonstration were to illustrate the benefits of growth promoting technologies for calves post-weaning. Calves (n = 39 heifers and 24 steers; BW = 229 ± 23.9 kg) from the OSU Eastern Research Station cowherd were weaned on day – 20 (April 15) and preconditioned. On day 0 (May 6), calves (n = 20 heifers and 12 steers) were treated for internal parasites (Dectomax, Zoetis Animal Health) and evenly allocated to 2 Bermudagrass/tall fescue pastures (9.5 ± 1.42 ha) for 143 days. The remaining calves (n = 19 heifers and 12 steers) were not treated for parasites and allocated to 2 pastures (9.1 ± 1.42 ha). In each pasture, ½ of the calves of each sex were implanted (Synovex-S or Synovex-H, Zoetis). Calves dewormed on day 0 and were dewormed again on day 70 (July 16). Data were analyzed as a split plot experimental design with dewormer treatment as the main plot and calf sex and implant treatment were the split plots. There were no interactions among calf sex, deworming, and implants (P ≥ 0.42). Steers were heavier (P < 0.01) than heifers throughout the summer, but did not have an advantage in gain performance (P ≥ 0.22). Deworming did not impact (P = 0.44) overall growth performance of calves, but did numerically (P = 0.18) increase ADG from day 71 to 143 by 0.15 kg/d. Growth promoting implants increased (P = 0.03) daily gains by 0.09 kg/day in the early summer and over the entire summer by 0.07 kg/day (P < 0.01). The combination of deworming and implants increased (P = 0.01) season long ADG by 0.11 kg/day over unimplanted controls. This demonstration was used to illustrate the potential that growth promoting implants and deworming provides for economically beneficial performance enhancement for retained stocker calves on mixed grass pasture.

scholarly journals Response of potato clones to planting dates in Pokhara, Kaski, Nepal

2020 ◽  
Vol 3 (2) ◽  
pp. 175-183
Author(s):  
Saroj Adhikari ◽  
Arvind Kumar Srivastava ◽  
Mohadutta Sharma ◽  
Arjun Kumar Shrestha
Keyword(s):  
Block Design ◽  
Growth Yield ◽  
Ground Cover ◽  
Potato Production ◽  
Tuber Number ◽  
Research Station ◽  
Planting Dates ◽  
Large Size ◽  
Two Factors ◽  
Size Tuber

A field trial was conducted to optimize the planting date and appropriate clone for ware potato production at Horticulture Research Station, Malepatan, Pokhara from October 2015 to March 2016. The trial was laid out in two factors Factorial Randomized Complete Block Design. There were nine treatments with three replications. The treatments comprised of three dates of planting (30th October, 14th and 29th November) and three potato clones (Janakdev, Lbr 40 and PRP 266264.1). The results showed that the main effects of planting dates and potato clones significantly (P<0.05) affected most growth, yield and yield attributing parameters of the crop. Interaction effect of planting dates and potato clones also significantly influenced the number of above-ground stems per plant, ground cover percentage, number of tubers per plant, number and weight of small size tuber (<25 g), weight of medium or seed size (25-50 g) tuber and large size (>50 g) tuber, number and yield of tubers per plot, and yield t/ha. The highest yield (37.05 t/ha) was obtained from 14th November planting. The clone Lbr 40 produced a higher yield (36.05t/ha). The clone PRP 266264.1 planting on 30th October planting produced significantly a higher yield (41.34t/ha). The clone Lbr 40 produced significantly highest number and weight of large size (>50 g) tuber. Number of small size (<25 g) tuber per plot or unmarketable tuber significantly increased on delayed planting.

scholarly journals Increase in perennial forage yields driven by climate change, at Apukka Research Station, Rovaniemi, 1980-2017

2020 ◽  
Vol 29 (2) ◽  
Author(s):  
Oiva Niemeläinen ◽  
Antti Hannukkala ◽  
Lauri Jauhiainen ◽  
Kaija Hakala ◽  
Markku Niskanen ◽  
...  
Keyword(s):  
Climate Change ◽  
Festuca Arundinacea ◽  
Ground Cover ◽  
Growing Season ◽  
Phleum Pratense ◽  
Research Station ◽  
Strong Impact ◽  
Meadow Fescue ◽  
Forage Crops ◽  
The North

The official variety trials at Rovaniemi, Finland (66.58°N, 26.01°E) in 1980–2017 show a substantial increase in dry matter yields (DMY) of timothy (Phleum pratense), meadow fescue (Festuca pratensis) and tall fescue (Festuca arundinacea), coinciding with a 156 °Cd increase in the average growing season Tsum and a 461 °Cd decrease in the average winter frost sum for the same period. The annual DMY of timothy was 3128, 4668, 8385 and 9352 kg ha-1 in the periods (P) 1980–1989 (P1), 1990–1999 (P2), 2000–2009 (P3), and 2010–2017 (P4). The first cut yielded 1792, 2166, 4008 and 4473, and the second cut 1337, 2503, 4378 and 4879 kg ha-1, respectively. Yields of meadow fescue followed a similar pattern. The first cut was about ten days and the second cut about one week earlier on P4 than on P1. Shorter snow cover period, milder winters, higher live ground cover of timothy in spring, and higher temperature sum during the growing season were most likely responsible for the yield increase. The results indicate a strong impact of climate change on DMY of perennial forage crops in the north.

THE EFFECT OF ORCHARD SOIL MANAGEMENT ON SOIL TEMPERATURE AND APPLE TREE NUTRITION

1986 ◽  
Vol 66 (4) ◽  
pp. 701-711 ◽  
Author(s):  
G. H. NEILSEN ◽  
E. J. HOGUE ◽  
B. G. DROUGHT
Keyword(s):  
Soil Temperature ◽  
Extreme Temperature ◽  
Ground Cover ◽  
Soil Management ◽  
Research Station ◽  
Vegetation Control ◽  
Plastic Mulching ◽  
Soil Temperatures ◽  
Summer Maximum ◽  
Black Plastic

Soil temperature was measured from 1981 to 1985 at 0.2- and 1.0-m depths for four soil management treatments which included full ground cover, total vegetation control, shallow tillage and black plastic mulching in a high-density orchard planted to Bisbee Red Delicious (Malus domestica Borkh.) on Mailing 26 rootstock. Ground cover suppression treatments, especially black plastic mulching, increased degree day accumulations above 10 °C in all 5 yr at 0.2-m and in 3 yr at 1.0-m depths relative to full ground cover. However, these treatments also resulted in more extreme temperature fluctuations as characterized by higher summer maximum and lower winter minimum temperatures under black plastic mulching. Despite a potential for more extreme soil temperatures, apple yield was significantly higher under black plastic relative to full ground cover. For these two contrasting temperature treatments, leaf N and Mg concentrations were usually significantly higher under black plastic while leaf P and K were consistently higher and leaf Ca and Zn were occasionally higher under full ground cover. Most of these differences were, with the possible exception of leaf Zn, attributed to the competition for, or recycling of, nutrients by orchard floor vegetation. Mean monthly soil temperatures at the two depths under the four soil management treatments could be predicted by simple linear regression techniques from soil temperature measurements at the Summerland Research Station Meteorological Recording Site. Key words: Bisbee Delicious apples, degree days, ground cover, suppression, black plastic mulching, leaf nutrition

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