scholarly journals Impact of potato psyllid density and timing of infestation on Zebra chip disease expression in potato plants

2016 ◽  
Vol 52 (No. 4) ◽  
pp. 262-269 ◽  
Author(s):  
Gao Feng ◽  
Zhao Zi-Hua ◽  
Jifon John ◽  
Liu Tong-Xian
Keyword(s):  
Tuber Yield ◽  
Potato Crop ◽  
Growth Stages ◽  
Potato Psyllid ◽  
Zebra Chip ◽  
Potato Plants ◽  
Zebra Chip Disease ◽  
Crop Development ◽  
The Impact ◽  
Different Growth Stages

The impact of vector density and timing of infestation on potato were investigated. Healthy potato plants at different growth stages (4, 5, and 7 weeks after germination) were exposed separately to four different B. cockerelli densities (0, 5, 20, and 40 psyllids per cage) in field cages and Zebra chip (ZC) symptoms, leaf photosynthetic rates, tuber yield, and total nonstructural carbohydrate accumulation in leaves and tubers of healthy and B. cockerelli-infested plants were monitored. Potato psyllid nymph and egg populations reached a seasonal peak at 6 weeks after the exposure to insect. Younger plants at 4-week growth stage after germination were more susceptible to B. cockerelli infestation and ZC expression than older plants. As few as five B. cockerelli adults were enough to transmit the ZC pathogen and cause ZC expression both in foliage and tuber. At the density of 20 psyllids per cage, more than 50% of plants showed ZC symptoms in tubers. Furthermore, B. cockerelli infestation reduced leaf photosynthesis rates (P<sub>n</sub>), resulting in less starch and more reducing sugars in tubers, and hence reduced tuber weight and yield, especially when psyllid infestation occurred at the early growth stages. The results indicate that early B. cockerelli infestation of younger plants was associated with more severe ZC expression in both foliage and tubers, leading to earlier dead plants. The data suggest that strategies for controlling B. cockerelli during early potato crop development could thus lessen the severity of ZC development.

scholarly journals A field study of Bactericera cockerelli feeding timing in potato crops

2017 ◽  
Vol 70 ◽  
pp. 320
Author(s):  
J.N. Furlong ◽  
J. Vereijssen ◽  
A.R. Pitman ◽  
R.C. Butler
Keyword(s):  
Growth Stages ◽  
Insect Vector ◽  
Bactericera Cockerelli ◽  
Zebra Chip ◽  
Growing Seasons ◽  
Yield And Quality ◽  
Zebra Chip Disease ◽  
Candidatus Liberibacter ◽  
Potato Crops ◽  
Different Growth Stages

Since its 2006 detection in New Zealand, the tomato potato psyllid (TPP), Bactericera cockerelli, has been responsible for yield and quality-reducing damage to potatoes as well as to other solanaceous crops. TPP is best known as the insect vector for the zebra chip disease-associated bacterium Candidatus Liberibacter solanacearum (CLso), but feeding by CLso-negative TPP on potatoes is also linked to damaging effects. An improved understanding of which potato plant physiological stages are most affected by feeding of CLso-negative TPP will allow for more directed integrated pest management (IPM) plans. As part of a two-year repeated eld study to assess the effect of TPP feeding timing on potatoes, CLso-negative TPP were released into mesh cages over outdoor potato (‘Moonlight’) plantings at ve different growth stages: post-emergence, owering, post- owering, late-season, and pre-harvest. Tubers were grouped by plant at harvest. (Un)marketable numbers and weights, marketable dry matter and zebra chip severity were determined. Results from this trial and other shadehouse trials conducted previously are still being analysed but have the potential to better target IPM plans and reduce costly, labour-intensive, and environmentally impactful pesticide spray use, which is currently relied on heavily throughout growing seasons.

scholarly journals Relative Abundance of Potato Psyllid Haplotypes in Southern Idaho Potato Fields During 2012 to 2015, and Incidence of ‘Candidatus Liberibacter solanacearum’ Causing Zebra Chip Disease

Plant Disease ◽  
2017 ◽  
Vol 101 (5) ◽  
pp. 822-829 ◽  
Author(s):  
Jennifer Dahan ◽  
Erik J. Wenninger ◽  
Brandon Thompson ◽  
Sahar Eid ◽  
Nora Olsen ◽  
...  
Keyword(s):  
Potato Industry ◽  
Potato Psyllid ◽  
Bactericera Cockerelli ◽  
Zebra Chip ◽  
Spatial And Temporal Patterns ◽  
Candidatus Liberibacter Solanacearum ◽  
South Central ◽  
Zebra Chip Disease ◽  
Four Seasons ◽  
Candidatus Liberibacter

Zebra chip (ZC) disease, a serious threat to the potato industry, is caused by the bacterium ‘Candidatus Liberibacter solanacearum’ (Lso). Five haplotypes (hapA to hapE) of this pathogen have been described so far in different crops, with only hapA and hapB being associated with ZC in potato. Both haplotypes are vectored and transmitted to a variety of solanaceaeous plants by the tomato/potato psyllid, Bactericera cockerelli (Šulc). Psyllids are native to North America, and four haplotypes have been identified and named based on their predominant geographic association: Northwestern, Central, Western, and Southwestern. Although all psyllid haplotypes have been found in southern Idaho potato fields, data on relative haplotype abundances and dynamic changes in the fields over time have not previously been reported. Here, psyllid samples collected in Idaho potato fields from 2012 to 2015 were used to clarify spatial and temporal patterns in distribution and abundance of psyllid and Lso haplotypes. A shift from hapA toward hapB population of Lso was revealed during these four seasons, indicating possible evolution of Lso in Idaho fields. Although we confirmed that Western psyllids were the most abundant by far during the four seasons of observation, we also observed changes in abundance of other haplotypes, including increased diversity of psyllid haplotypes during 2015. Seasonal changes observed for the Northwestern and Central haplotypes could potentially be linked to psyllid migration and/or habitat changes. South-central Idaho exhibited more diversity in psyllid haplotypes than southwestern Idaho.

scholarly journals Response of Cotton Varieties to the Stage of Topping under Rainfed Condition of Bardiya, Nepal

2006 ◽  
Vol 27 ◽  
pp. 165-168 ◽  
Author(s):  
KB Basnet
Keyword(s):  
Block Design ◽  
Growth Stages ◽  
Cotton Yield ◽  
Seed Cotton ◽  
Rainfed Condition ◽  
Seed Cotton Yield ◽  
Significant Difference ◽  
The Difference ◽  
The Impact ◽  
Different Growth Stages

A field experiment was conducted to study the impact of topping at different growth stages (3-4, 6-7, 9-10 and 12-13 sympodial branches) on productivity of two (Tamcot SP-37 and H-777) cotton varieties under rainfed condition at the Kumbher Farm (Bardiya district) of Cotton Development Board in 1995. The experiment was laid out in a Randomized Complete Block Design with four replications. The interaction effect between variety and stages of topping showed that significantly higher yield (1.23 t/ha) was produced by topping plants at the stage of 12-13 sympodial banches of the variety Tamcot SP-37 as compared to all other treatments. At all stages of topping the yield produced by Tamcot SP-37 was significantly higher than H-777. The average seed cotton yield (1.03 t/ha) of Tamcot SP-37 was significantly higher than that of H- 777 (0.71 t/ha) and the difference in yield was 45.0%. The seed-cotton yield increased from 0.75 to 1.00 t/ ha with the postponed of topping from 3-4 to 12-13 sympodial branches, but significant difference was recorded between late (12-13 sympodial branches) and early (3-4 and 6-7 sympodial branches) stages of topping. Thus, for rainfed condition of Bardiya Tamcot SP-37 was a suitable variety with 12-13 sympodial branches as an appropriate stage of topping for sustainable production of cotton. Key words: Variety, topping, sympodial branches. J. Inst. Agric. Anim. Sci. 27:165-168 (2006)

scholarly journals Crop coefficient of a popular potato variety in Bangladesh

2017 ◽  
Vol 42 (1) ◽  
pp. 67-76
Author(s):  
AR Akanda ◽  
MS Rahman ◽  
MS Islam ◽  
AJ Mila
Keyword(s):  
Potato Variety ◽  
Tuber Yield ◽  
Agricultural Research ◽  
Crop Coefficient ◽  
Climatic Conditions ◽  
Growth Stages ◽  
Crop Evapotranspiration ◽  
Agricultural Research Institute ◽  
Initial Development ◽  
Different Growth Stages

Crop evapotranspiration (ETc) and crop coefficient (Kc) values of potato (variety: BARI Alu -7, Diamant) at different growth stages were determined through lysimeter method at Irrigation and Water Management Division of Bangladesh Agricultural Research Institute (BARI), Gazipur during 2008 - 2009. The study was conducted by applying irrigation at 25 and 40 days after planting (DAP) allowing drainage (AD) (T1), at 25, 40, and 55 DAP AD (T2), at 25, 40, and 60 DAP AD (T3), and at 25, 40, 55, and 60 DAP AD (T4) within and adjacent of four lysimeter tanks. Irrigation at 25, 40, and 55 DAP produced the highest tuber yield and was considered to be suitable for estimating seasonal ETc, and Kc values. The seasonal highest ETc was found to be 162 mm. The Kc values of 0.25, 0.62, 0.70 and 0.18 were determined at initial, development, midseason and late season stages of potato. These values differed slightly from the FAO recommended values. As the lysimeter provides control environment, the Kc values determined by this method are most dependable and recommended for estimating ETc of potato in semi-arid climatic conditions of Bangladesh.Bangladesh J. Agril. Res. 42(1): 67-76, March 2017

scholarly journals Characterization and Epidemiological Significance of Potato Plants Grown from Seed Tubers Affected by Zebra Chip Disease

Plant Disease ◽  
2010 ◽  
Vol 94 (6) ◽  
pp. 659-665 ◽  
Author(s):  
D. C. Henne ◽  
F. Workneh ◽  
A. Wen ◽  
J. A. Price ◽  
J. S. Pasche ◽  
...  
Keyword(s):  
United States ◽  
The United States ◽  
Zebra Chip ◽  
Candidatus Liberibacter Solanacearum ◽  
Potato Plants ◽  
Seed Tubers ◽  
Zebra Chip Disease ◽  
Candidatus Liberibacter ◽  
Epidemiological Significance

An emerging disease of potato in the United States, known as “Zebra Chip” or “Zebra Complex” (ZC), is increasing in scope and threatens to spread further. Here, we report on studies performed to understand the role of tuberborne ZC in the epidemiology of this disease. Depending on variety, up to 44% of ZC-affected seed tubers (ZCST) were viable, producing hair sprouts and weak plants. Chip discoloration in progeny tubers of ZCST was more severe than those from ZC-asymptomatic seed tubers but varied depending on whether progeny tubers or foliage were positive or negative for ‘Candidatus Liberibacter solanacearum’. A low percentage of greenhouse-grown plants produced by ZCST tested positive for ‘Ca. Liberibacter’. No adult potato psyllids became infective after feeding upon these plants but they did acquire ‘Ca. Liberibacter’ from field-grown plants produced by ZCST. Plants with new ZC infections near plants produced by ZCST were not significantly different from healthy plants, whereas plants affected with ZC from infectious potato psyllids had significantly more ZC infections near either plants produced by ZCST or healthy plants. We conclude that, in areas where ZC is currently established, plants produced by ZCST do not significantly contribute to ZC incidence and spread within potato fields.

scholarly journals The impact of climatic variability and climate change on arabic coffee crop in Brazil

Bragantia ◽  
2010 ◽  
Vol 69 (1) ◽  
pp. 239-247 ◽  
Author(s):  
Marcelo Bento Paes de Camargo
Keyword(s):  
Climate Change ◽  
Soil Water ◽  
Climatic Factors ◽  
Climatic Variability ◽  
Growth Stages ◽  
Coffee Production ◽  
Potential Yield ◽  
Intergovernmental Panel ◽  
The Impact ◽  
Different Growth Stages

The climatic variability is the main factor responsible for the oscillations and frustrations of the coffee grain yield in Brazil. The relationships between the climatic parameters and the agricultural production are quite complex, because environmental factors affect the growth and the development of the plants under different forms during the growth stages of the coffee crop. Agrometeorological models related to the growth, development and productivity can supply information for the soil water monitoring and yield forecast, based on the water stress. A soil water balance during different growth stages of the coffee crop, can quantify the effect of the available soil water on the decrease of the final yield. Other climatic factors can reduce the productivity, such as adverse air temperatures happened during different growth stages. Solar radiation and relative humidity influence many physiological processes of the coffee tree but are not generally thought to play an important role as thermal and rainfall conditions in defining potential yield or ecological limitations for this crop. According to the last report of the Intergovernmental Panel on Climate Change (IPCC, 2007), the global temperature is supposed to increase 1.1ºC to 6.4ºC and the rainfall 15% in the tropical areas of Brazil. Some Global warming projections as presented by IPCC will cause a strong decrease in the coffee production in Brazil. According to the literature besides the reduction of suitable areas for coffee production, the crop will tend to move South and uphill regions. This review article analyze the effect that these possible scenarios would have in the agro-climatic coffee zoning in Brazil, and adaptive solutions, such as agronomic mitigations and development of cultivars adapted to high temperatures is considered.

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