Dataset Information

Citrus Production Under Screen as a Strategy to Protect Grapefruit Trees From Huanglongbing Disease.

ABSTRACT: Citrus production under enclosed structures can exclude the Asian citrus psyllid (ACP, Diaphorina citri) and eliminate the negative effects of citrus greening or huanglongbing (HLB) disease caused by Candidatus Liberibacter asiaticus to the grapefruit (Citrus paradisi) fresh fruit industry. Physically impeding the insect vector from accessing trees is a logical method to have disease-free groves. Our objectives were to assess the ability of enclosed screenhouses to exclude the ACP, stop HLB inoculation and dissemination, and improve fruit yield of in-ground and container-grown 6-year-old "Ray Ruby" grapefruit at super-high planting densities relative to open-air trees. We built a large structure to allow commercial-scale trials and tested two production systems (screenhouse and open-air), two planting systems (in-ground and potted), and two rootstocks ("Sour Orange" [Citrus × aurantium] and "US-897" [Citrus reticulata × Poncirus trifoliate]). The experimental design was a randomized complete block design split-split-plot with four replications. Four passively ventilated 1,080-m2 completely enclosed screenhouses were constructed using a 50-mesh monofilament high-density polyethylene screen. The main support for each enclosed, covered structure consisted of pressure-treated, wooden utility poles. Trees were planted in Sept/2013 on a density of 1,957 trees/ha. Irrigation was performed on-demand using two 7.6-LPH drip emitters per tree, and fertigation was applied three times/week using 15N-2.6P-22.4K water-soluble fertilizer at 180 kg N/ha. Psyllids were monitored using sticky cards and detected inside the screenhouses post-Hurricane Irma, which damaged the screen structures in Sept/2017, leaving openings until repairs were completed in Apr/2018. Screen aging and a tropical storm in April/2019 caused another major screen opening fixed in Oct/2019. Despite the weather-related damages to the screens, only trees cultivated in open-air tested positive for Candidatus Liberibacter asiaticus after 6 years. There was fast disease progression for all outside treatments, with 100% infection. Covered, in-ground trees exhibited the highest trunk diameter and canopy volume (P < 0.0001). Trees grown inside screenhouses exhibited higher fruit yield than outside trees, with the highest yield observed for in-ground trees on "US-897" (51,081 kg/ha) (P < 0.0001). Several open-air treatments particularly in containers did not produce any fruit. On the other hand, potted grapefruit trees cultivated inside the enclosures had the highest soluble solids content (P < 0.001). The screenhouses provided disease exclusion, increased fruit yield, and fruit quality, representing an alternative for growers interested in producing high-quality fruit for the fresh market. Production cost and economic viability still need to be evaluated for large-scale implementation.

SUBMITTER: Ferrarezi RS

PROVIDER: S-EPMC6930270 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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Citrus Production Under Screen as a Strategy to Protect Grapefruit Trees From Huanglongbing Disease.

Ferrarezi Rhuanito S RS Qureshi Jawwad A JA Wright Alan L AL Ritenour Mark A MA Macan Natalia P F NPF

Frontiers in plant science 20191218

Citrus production under enclosed structures can exclude the Asian citrus psyllid (ACP, Diaphorina citri) and eliminate the negative effects of citrus greening or huanglongbing (HLB) disease caused by Candidatus Liberibacter asiaticus to the grapefruit (Citrus paradisi) fresh fruit industry. Physically impeding the insect vector from accessing trees is a logical method to have disease-free groves. Our objectives were to assess the ability of enclosed screenhouses to exclude t ...[more]

PMID: 31921247

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Project description:In this data set, we reported for the first time that huanglongbing disease (HLB) induces major changes in the expression of global genes in flavedo, vascular and juice vesicle tissues of citrus fruit. 68 Total samples were analyzed. cDNA generation, array analysis, and statistical tests were performed as a service at the Interdisciplinary Center for Biotechnology Research (ICBR) Microarray Core facility at the University of Florida (Gainesville, FL). The linear models were used for array analysis (Smyth GK et al. Bioinformatics, 2005, 2067-2075). The linear models were firstly used to assess differential expression, and then an empirical Bayes method was used to moderate the standard errors. 13 comparisons were performed for the study. The comparisons in Citrus sinensis cv. Hamlin included: SC vs. CC (genes that respond to infection in symptomatic vascular core); SJV vs. CJV (genes that respond to infection in symptomatic juice vesicle); SS vs. CS (genes that respond to infection in symptomatic seed); SP vs. CP (genes that respond to infection in symptomatic peel). The comparisons in Citrus sinensis cv. Valencia included: SP vs. HP (genes that respond to infection in symptomatic peel); ASP vs. HP (genes that respond to infection in asymptomatic peel); SP vs. ASP (genes that respond to infection in symptomatic peel compared to asymptomatic peel); SC vs. HC (genes that respond to infection in symptomatic vascular core); ASC vs. HC (genes that respond to infection in asymptomatic vascular core); SC vs. ASC (genes that respond to infection in symptomatic vascular core compared to asymptomatic vascular core); SJV vs. HJV (genes that respond to infection in symptomatic juice vesicle); ASJV vs. HJV (genes that respond to infection in asymptomatic juice vesicle); SJV vs. ASJV (genes that respond to infection in symptomatic juice vesicle compared to asymptomatic juice vesicle). ESTs with significant expression changes (P value <0.001; false discovery rate <0.01 with equal or higher than 2-fold changes in expression) were selected for further analysis.

Project description:The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is the key pest of citrus wherever it occurs due to its role as vector of huanglongbing (HLB) also known as citrus greening disease. Insecticidal vector control is considered to be the primary strategy for HLB management and is typically intense owing to the severity of this disease. While this approach slows spread and also decreases severity of HLB once the disease is established, economic viability of increasingly frequent sprays is uncertain. Lacking until now were studies evaluating the optimum frequency of insecticide applications to mature trees during the growing season under conditions of high HLB incidence. We related different degrees of insecticide control with ACP abundance and ultimately, with HLB-associated yield losses in two four-year replicated experiments conducted in commercial groves of mature orange trees under high HLB incidence. Decisions on insecticide applications directed at ACP were made by project managers and confined to designated plots according to experimental design. All operational costs as well as production benefits were taken into account for economic analysis. The relationship between management costs, ACP abundance and HLB-associated economic losses based on current prices for process oranges was used to determine the optimum frequency and timing for insecticide applications during the growing season. Trees under the most intensive insecticidal control harbored fewest ACP resulting in greatest yields. The relationship between vector densities and yield loss was significant but differed between the two test orchards, possibly due to varying initial HLB infection levels, ACP populations or cultivar response. Based on these relationships, treatment thresholds during the growing season were obtained as a function of application costs, juice market prices and ACP densities. A conservative threshold for mature trees with high incidence of HLB would help maintain economic viability by reducing excessive insecticide sprays, thereby leaving more room for non-aggressive management tools such as biological control.

Dataset Information

Citrus Production Under Screen as a Strategy to Protect Grapefruit Trees From Huanglongbing Disease.

Publications

Citrus Production Under Screen as a Strategy to Protect Grapefruit Trees From Huanglongbing Disease.

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