Attractant and repellent effects of sweet potato root exudates on the potato rot nematode, Ditylenchus destructor

Nematology ◽  
2015 ◽  
Vol 17 (1) ◽  
pp. 117-124 ◽  
Author(s):  
Zhen Xu ◽  
Yong-Qiang Zhao ◽  
Dong-Jing Yang ◽  
Hou-Jun Sun ◽  
Cheng-Ling Zhang ◽  
...  
Keyword(s):  
Sweet Potato ◽  
Root Exudates ◽  
Host Location ◽  
Field Experiments ◽  
Control Method ◽  
Northern Region ◽  
Effective Control ◽  
Potato Plants ◽  
Seedling Roots ◽  
Ditylenchus Destructor

Potato rot nematode (Ditylenchus destructor) is one of the most damaging pests of sweet potato in the northern region of China. Glasshouse and field experiments were conducted to explore the main invasion route used by potato rot nematodes during infection of sweet potato plants. The nematode’s host location behaviour was also investigated. Results suggested that substantial yield losses of sweet potato caused by D. destructor parasitism depend upon the existence of wounds on seedling roots. Therefore, reducing the number of nematodes that invade through such wounds would be an effective control method. We found that root exudates and extracts from underground stems of both resistant (cv. Zhenghong 22) and susceptible (cv. Lizixiang) sweet potato cultivars attracted potato rot nematodes. In addition, a strong repellent effect of latex against these nematodes was observed in both cultivars. Interestingly, octadecyl-(Z)-p-coumarate, a component of sweet potato latex, acted as a repellent for potato rot nematodes, while hexadecyl- and eicosyl-(Z)-p-coumarates did not. These findings provide a basis for understanding the mechanism underlying the host location behaviour of potato rot nematodes and can help in designing new nematode control methods.

scholarly journals Tomato spotted wilt virus Can Infect Resistant Tomato when Western Flower Thrips Inoculate Blossoms

Plant Disease ◽  
2017 ◽  
Vol 101 (9) ◽  
pp. 1666-1670 ◽  
Author(s):  
J. L. Houle ◽  
G. G. Kennedy
Keyword(s):  
Tomato Spotted Wilt Virus ◽  
Frankliniella Occidentalis ◽  
Field Experiments ◽  
Control Method ◽  
Western Flower Thrips ◽  
Effective Control ◽  
Flower Thrips ◽  
Tomato Spotted Wilt ◽  
Systemic Infections ◽  
Wilt Virus

Tomato spotted wilt is a major disease of crops worldwide. Resistant cultivars carrying the Sw-5 allele for resistance to tomato spotted wilt disease (TSW) provide the most effective control method in tomato (Solanum lycopersicum). However, infections of fruit on Sw-5+ tomato plants suggest the virus resistance may not be fully expressed in blossoms or developing fruit. The objective of this study was to determine if the thrips vector, the western flower thrips (Frankliniella occidentalis), can transmit non-resistance breaking Tomato spotted wilt virus (TSWV) isolates when confined to blossoms on plants with and without the Sw-5 resistance allele. Twenty-one percent of 33 Sw-5+ plants inoculated by adult thrips feeding on blossom clusters or small fruit developed infections in the reproductive tissue, whereas 68% of 25 Sw-5– plants developed infections. Systemic infections also occurred following inoculation of blossoms in host genotypes with and without Sw-5. These results were further supported by field experiments that showed high proportions of infected fruit as well as a limited infection of foliage on the same stem as the infected fruit in Sw-5+ plants when F. occidentalis were abundant in blossoms. These findings help to explain observations of abundant late season infections of Sw-5 cultivars in commercial plantings and suggest that management of F. occidentalis infestations during the bloom period may be important for effective management of TSWV in susceptible tomato cultivars as well as cultivars expressing the Sw-5 allele for TSW resistance.

scholarly journals A New Model Predictive Control Method for Eliminating Hydraulic Oscillation and Dynamic Hydraulic Imbalance in a Complex Chilled Water System

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3608
Author(s):  
Yang Yuan ◽  
Neng Zhu ◽  
Haizhu Zhou ◽  
Hai Wang
Keyword(s):  
Model Predictive Control ◽  
Predictive Control ◽  
Control Method ◽  
Water System ◽  
Energy Performance ◽  
Effective Control ◽  
New Model ◽  
Chilled Water ◽  
Chilled Water System ◽  
Hydraulic Oscillation

To enhance the energy performance of a central air-conditioning system, an effective control method for the chilled water system is always essential. However, it is a real challenge to distribute exact cooling energy to multiple terminal units in different floors via a complex chilled water network. To mitigate hydraulic imbalance in a complex chilled water system, many throttle valves and variable-speed pumps are installed, which are usually regulated by PID-based controllers. Due to the severe hydraulic coupling among the valves and pumps, the hydraulic oscillation phenomena often occur while using those feedback-based controllers. Based on a data-calibrated water distribution model which can accurately predict the hydraulic behaviors of a chilled water system, a new Model Predictive Control (MPC) method is proposed in this study. The proposed method is validated by a real-life chilled water system in a 22-floor hotel. By the proposed method, the valves and pumps can be regulated safely without any hydraulic oscillations. Simultaneously, the hydraulic imbalance among different floors is also eliminated, which can save 23.3% electricity consumption of the pumps.

KIH-485 and S-metolachlor Efficacy Comparisons in Conventional and No-Tillage Corn

2006 ◽  
Vol 20 (3) ◽  
pp. 622-626 ◽  
Author(s):  
Patrick W. Geier ◽  
Phillip W. Stahlman ◽  
John C. Frihauf
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Conventional Tillage ◽  
Palmer Amaranth ◽  
Effective Control ◽  
No Tillage ◽  
Green Foxtail

Field experiments were conducted during 2003 and 2004 to compare the effectiveness of KIH-485 and S-metolachlor for PRE weed control in no-tillage and conventional-tillage corn. Longspine sandbur control increased as KIH-485 or S-metolachlor rates increased in conventional-tillage corn, but control did not exceed 75% when averaged over experiments. Both herbicides controlled at least 87% of green foxtail with the exception of no-tillage corn in 2004, when KIH-485 was more effective than S-metolachlor at lower rates. Palmer amaranth control ranged from 85 to 100% in 2003 and 80 to 100% in 2004, with the exception of only 57 to 76% control at the lowest two S-metolachlor rates in 2004. Puncturevine control exceeded 94% with all treatments in 2003. In 2004, KIH-485 controlled 86 to 96% of the puncturevine, whereas S-metolachlor controlled only 70 to 81%. Mixtures of atrazine with KIH-485 or S-metolachlor generally provided the most effective control of broadleaf weeds studied.

Fungicidal control of leaf spot (Septoria apiicola) of celery

1989 ◽  
Vol 29 (2) ◽  
pp. 261 ◽  
Author(s):  
TJ Wicks
Keyword(s):  
Leaf Spot ◽  
Field Experiments ◽  
Effective Control ◽  
Severity Of Disease

Ten fungicides were evaluated and compared in glasshouse and field experiments for the control of celery leaf spot caused by Septoria apiicola. In glasshouse experiments propiconazole (25 mg a.i. L-1) inhibited the development of S. apiicola when applied to celery seedlings 2 days after inoculation and in 1 experiment an application 8 days after inoculation reduced by 10-fold the severity of disease as well as the production of pycnidia. Penconazole (25 mg a.i. L-1), myclobutanil (50 mg a.i. L-1), flusilazole (20 mg a.i. L-1), fenarimol (36 mg a.i. L-1), terbuconazole (25 mg a.i. L-1) and triadimenol(25 mg a.i. L-1) also controlled S. apiicola when applied 2, but not 8 days, after inoculation. Anilazine protected celery seedlings for at least 13 days after application and was the most effective of the fungicides applied before infection. In field experiments, the most effective control of leaf spot was achieved with applications, every 7-10 days, of anilazine (1500 mg a.i. L-1), applied either alone or mixed with propiconazole (25 mg a.i. L-1). Similar applications of propiconazole either alone or mixed with chlorothalonil (150 mg a.i. L-1) also controlled leaf spot, whereas penconazole (25 mg a.i. L-1), flusilazole (20 mg a.i. L-1) and myclobutanil (50 mg a.i. L-1) were not effective.

Accumulation of carbon and nitrogen compounds in sweet potato plants grown under deficiency of N, P, or K nutrients

1995 ◽  
Vol 41 (3) ◽  
pp. 557-566 ◽  
Author(s):  
Mitsuru Osaki ◽  
Hiroyuki Ueda ◽  
Takuro Shinano ◽  
Hirokazu Matsui ◽  
Toshiaki Tadano
Keyword(s):  
Sweet Potato ◽  
Nitrogen Compounds ◽  
Carbon And Nitrogen ◽  
Potato Plants

scholarly journals Reduced Dosage of Methyl Bromide for Controlling Verticillium Wilt of Potato in Experimental and Commercial Plots

Plant Disease ◽  
1997 ◽  
Vol 81 (5) ◽  
pp. 469-474 ◽  
Author(s):  
A. Gamliel ◽  
A. Grinstein ◽  
Y. Peretz ◽  
L. Klein ◽  
A. Nachmias ◽  
...  
Keyword(s):  
Verticillium Wilt ◽  
Methyl Bromide ◽  
Large Scale ◽  
Field Experiments ◽  
Tuber Yield ◽  
Total Yield ◽  
Effective Control ◽  
Large Scale Field ◽  
Commercial Applications

The use of gas-impermeable films to reduce the dosage of methyl bromide (MB) required to control Verticillium wilt in potatoes was examined in field experiments, conducted in soils naturally infested with Verticillium dahliae. The incidence and severity of Verticillium wilt were significantly reduced (by 74 to 94%) by fumigation with MB at 50 g/m2 under standard low density polyethylene (LDPE) or at 25 g/m2 under gas-impermeable films. Fumigation at 25 g/m2 under LDPE was less effective. Disease severity was inversely correlated (r2 = 0.89 to 0.91) with chlorophyll content in the leaves. Fumigation also reduced (by 89 to 100%) stem colonization by the pathogen. Potato yield in the fumigated plots was significantly higher (26 to 69%), than in their nonfumigated counterparts, and was inversely correlated with disease index (r2 = 0.69 to 0.9). The percentage of high-value tubers (above 45 g) was 52 to 56% of total yield in the fumigated plots as compared with 32 to 40% in the nonfumigated controls. Thus, fumigation also improved the commercial quality of tuber yield. Effective control of V. dahliae and yield increases following MB fumigation at the recommended dosage or at a reduced dosage with gas-impermeable films was also observed in a consecutive crop. These results were verified in a large-scale field experiment using commercial applications, further demonstrating the feasibility of reducing MB dosages under farm conditions, without reducing its effectiveness in terms of disease control and yield improvement.

scholarly journals Plant age and genotype affect the bacterial community composition in the tuber rhizosphere of field-grown sweet potato plants

2014 ◽  
Vol 88 (2) ◽  
pp. 424-435 ◽  
Author(s):  
Joana M. Marques ◽  
Thais F. da Silva ◽  
Renata E. Vollu ◽  
Arie F. Blank ◽  
Guo-Chun Ding ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Sweet Potato ◽  
Community Composition ◽  
Bacterial Community Composition ◽  
Plant Age ◽  
Potato Plants

scholarly journals Control of Volunteer Glyphosate-Resistant Canola in Glyphosate-Resistant Sugar Beet

2015 ◽  
Vol 29 (1) ◽  
pp. 93-100 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha
Keyword(s):  
Sugar Beet ◽  
Field Experiments ◽  
Agricultural Research ◽  
Effective Control ◽  
Additional Advantage ◽  
Leaf Stage ◽  
Beet Root ◽  
Control Volunteer ◽  
Sugar Beet Root ◽  
Herbicide Programs

Occurrence of glyphosate-resistant (GR) canola volunteers in GR sugar beet is a management concern for growers in the Northern Great Plains. Field experiments were conducted at the Southern Agricultural Research Center near Huntley, MT, in 2011 and 2012 to evaluate effective herbicide programs to control volunteer GR canola in GR sugar beet. Single POST application of triflusulfuron methyl alone at the two-leaf stage of sugar beet was more effective at 35 compared with 17.5 g ai ha−1. However, rate differences were not evident when triflusulfuron methyl was applied as a sequential POST (two-leaf followed by [fb] six-leaf stage of sugar beet) program (17.5 fb 17.5 or 35 fb 35 g ha−1). Volunteer GR canola plants in the sequential POST triflusulfuron methyl–containing treatments produced little biomass (11 to 15% of nontreated plots) but a significant amount of seeds (160 to 661 seeds m−2). Ethofumesate (4,200 g ai ha−1) PRE followed by sequential POST triflusulfuron methyl (17.5 or 35 g ha−1) provided effective control (94 to 98% at 30 d after treatment [DAT]), biomass reduction (97%), and seed prevention of volunteer GR canola. There was no additional advantage of adding either desmedipham + phenmedipham + ethofumesate premix (44.7 g ha−1) or ethofumesate (140 g ha−1) to the sequential POST triflusulfuron methyl–only treatments. The sequential POST ethofumesate-only (140 fb 140 g ha−1) treatment provided poor volunteer GR canola control at 30 DAT, and the noncontrolled plants produced 6,361 seeds m−2, which was comparable to the nontreated control (7,593 seeds m−2). Sequential POST triflusulfuron methyl–containing treatments reduced GR sugar beet root and sucrose yields to 18 and 20%, respectively. Consistent with GR canola control, sugar beet root and sucrose yields were highest (95 and 91% of hand-weeded plots, respectively) when the sequential POST triflusulfuron methyl–containing treatments were preceded by ethofumesate (4,200 g ha−1) PRE. Growers should utilize these effective herbicide programs to control volunteer GR canola in GR sugar beet. Because of high canola seed production potential, as evident from this research, control efforts should be aimed at preventing seed bank replenishment of the GR canola volunteers.

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