Botryosphaeria branch canker and dieback of avocado ( Persea americana Mill.) has expanded in avo... more Botryosphaeria branch canker and dieback of avocado ( Persea americana Mill.) has expanded in avocado-growing areas in recent years. Twenty-one avocado groves in the major producing regions of California were surveyed in 2018 and 2019. Monthly inoculations of wounded, green, and lignified branches of ‘Hass’ and ‘Lamb Hass’ were conducted. Botryosphaeriaceae were the predominant fungi recovered from cankered tissues collected across the surveyed traditional and high-density orchards and caused symptoms on all six sampled cultivars. These fungi were also recovered in asymptomatic twigs and other organs and thus exist as a potential reservoir for future infections. Molecular analyses of 173 isolates showed that Neofusicoccum luteum had the greatest incidences across sites and cultivars, with 83 and 29% recovered from Hass and Lamb Hass, respectively. Pathogenicity tests on excised (Hass, GEM, and Hass mutants) and attached shoots from potted (Hass) and mature avocado trees (Hass and La...
Journal of the American Society for Horticultural Science
Establishment of a controlled atmosphere (CA) of 2% O2 + 5% CO2 within one day of harvest (no del... more Establishment of a controlled atmosphere (CA) of 2% O2 + 5% CO2 within one day of harvest (no delay) or after a one-week delay in 0°C air retarded rapid softening of CA-stored kiwifruit (Actinidia chinensis Planch. ‘Hayward’) during the 1st 6 weeks of 0° storage, relative to those kept in air or in CA established after a 2-week delay. Between the 6th and 24th week of storage, further softening in air-stored fruit was suppressed in all CA treatments, and the 2-week delay CA fruit always were significantly softer than those placed in CA within one day of harvest. The one-week delay treatment resulted in an intermediate flesh firmness. The rates of fruit softening at 0°-air after 12, 16, or 24 weeks of CA storage were comparable to those of fruit stored continuously in 0° air.
Controlled and Modified Atmospheres for Fresh and Fresh-Cut Produce
Abstract Avocados are unique in the amount of oil they contain and that they will not ripen on th... more Abstract Avocados are unique in the amount of oil they contain and that they will not ripen on the tree. The key storage limitations after >≈4 weeks is flesh graying (or diffuse flesh discoloration), and stem end and body rots. Optimum storage temperature is ≈ 5–6°C where irregular skin blackening is a chilling response at low temperature (
Journal of the American Society for Horticultural Science
The effects of C2H4 concentration, duration and timing of exposure to C2H4, and temperature on st... more The effects of C2H4 concentration, duration and timing of exposure to C2H4, and temperature on storage performance of kiwifruit (Actinidia chinensis Planch. ‘Hayward’) kept in air or a controlled atmosphere (CA) of 2% O2 + 5% CO2 were investigated. The presence of 0.05, 0.1, 0.5, 1.0, or 5.0 μl·liter−1 C2H4 in CA accelerated softening and induced white core inclusions (WCI) which increased with storage time and C2H4 concentration. There was no difference between a 2-week or a 4-week exposure to 0.5 μl·liter−1 C2H4 at the beginning of CA storage in the extent of softening or WCI incidence and severity, but prolonged exposures accelerated deterioration. The softening rate of kiwifruit kept in air or CA increased with temperature. The incidence and severity of WCI were much greater in fruit kept in CA + 0.5 μl·liter−1 C2H4 at 0° or 2.5°C than in fruit stored at 5° or 10°.
Journal of the American Society for Horticultural Science
Kiwifruit from 3 growing locations were harvested at 4 maturity levels. Weight, length, width, fl... more Kiwifruit from 3 growing locations were harvested at 4 maturity levels. Weight, length, width, flesh color, flesh firmness, harvest soluble solids, titratable acidity, respiration, and ethylene production were measured at harvest, and subsequent storage behavior and sensory quality of the fruit were evaluated. The results indicate that a combination of initial soluble solids content at harvest, and flesh firmness, similar to the maturity index for pear, seems promising as a maturity index for kiwifruit.
SYNOPSIS The susceptibility of the avocado to both vibration and impaction as influenced by culti... more SYNOPSIS The susceptibility of the avocado to both vibration and impaction as influenced by cultivar, maturity and flesh firmness was studied. Emphasis was placed on the Hass variety since it comprises about 70 per cent of the total California acreage. External vibration injury (1,1 x g for 20, 40 or 60 min) is easily discernible in Fuerte, Pinkerton and early-season Hass fruit as surface discolouration. As the Hass variety darkens either during ripening or with maturity, the external symptoms of injury are masked. As flesh firmness decreases during ripening ( 6,8 kgf), prior to extensive softening, no appreciable damage is observed as a result of impaction (23, 46 or 92 cm). As flesh softening occurs, bruising due to impaction increases. Bruising is characterised by flesh discolouration sometimes extending into the seed cavity in soft fruit and occurred in all evaluated varieties.
Botryosphaeria branch canker and dieback of avocado ( Persea americana Mill.) has expanded in avo... more Botryosphaeria branch canker and dieback of avocado ( Persea americana Mill.) has expanded in avocado-growing areas in recent years. Twenty-one avocado groves in the major producing regions of California were surveyed in 2018 and 2019. Monthly inoculations of wounded, green, and lignified branches of ‘Hass’ and ‘Lamb Hass’ were conducted. Botryosphaeriaceae were the predominant fungi recovered from cankered tissues collected across the surveyed traditional and high-density orchards and caused symptoms on all six sampled cultivars. These fungi were also recovered in asymptomatic twigs and other organs and thus exist as a potential reservoir for future infections. Molecular analyses of 173 isolates showed that Neofusicoccum luteum had the greatest incidences across sites and cultivars, with 83 and 29% recovered from Hass and Lamb Hass, respectively. Pathogenicity tests on excised (Hass, GEM, and Hass mutants) and attached shoots from potted (Hass) and mature avocado trees (Hass and La...
Journal of the American Society for Horticultural Science
Establishment of a controlled atmosphere (CA) of 2% O2 + 5% CO2 within one day of harvest (no del... more Establishment of a controlled atmosphere (CA) of 2% O2 + 5% CO2 within one day of harvest (no delay) or after a one-week delay in 0°C air retarded rapid softening of CA-stored kiwifruit (Actinidia chinensis Planch. ‘Hayward’) during the 1st 6 weeks of 0° storage, relative to those kept in air or in CA established after a 2-week delay. Between the 6th and 24th week of storage, further softening in air-stored fruit was suppressed in all CA treatments, and the 2-week delay CA fruit always were significantly softer than those placed in CA within one day of harvest. The one-week delay treatment resulted in an intermediate flesh firmness. The rates of fruit softening at 0°-air after 12, 16, or 24 weeks of CA storage were comparable to those of fruit stored continuously in 0° air.
Controlled and Modified Atmospheres for Fresh and Fresh-Cut Produce
Abstract Avocados are unique in the amount of oil they contain and that they will not ripen on th... more Abstract Avocados are unique in the amount of oil they contain and that they will not ripen on the tree. The key storage limitations after >≈4 weeks is flesh graying (or diffuse flesh discoloration), and stem end and body rots. Optimum storage temperature is ≈ 5–6°C where irregular skin blackening is a chilling response at low temperature (
Journal of the American Society for Horticultural Science
The effects of C2H4 concentration, duration and timing of exposure to C2H4, and temperature on st... more The effects of C2H4 concentration, duration and timing of exposure to C2H4, and temperature on storage performance of kiwifruit (Actinidia chinensis Planch. ‘Hayward’) kept in air or a controlled atmosphere (CA) of 2% O2 + 5% CO2 were investigated. The presence of 0.05, 0.1, 0.5, 1.0, or 5.0 μl·liter−1 C2H4 in CA accelerated softening and induced white core inclusions (WCI) which increased with storage time and C2H4 concentration. There was no difference between a 2-week or a 4-week exposure to 0.5 μl·liter−1 C2H4 at the beginning of CA storage in the extent of softening or WCI incidence and severity, but prolonged exposures accelerated deterioration. The softening rate of kiwifruit kept in air or CA increased with temperature. The incidence and severity of WCI were much greater in fruit kept in CA + 0.5 μl·liter−1 C2H4 at 0° or 2.5°C than in fruit stored at 5° or 10°.
Journal of the American Society for Horticultural Science
Kiwifruit from 3 growing locations were harvested at 4 maturity levels. Weight, length, width, fl... more Kiwifruit from 3 growing locations were harvested at 4 maturity levels. Weight, length, width, flesh color, flesh firmness, harvest soluble solids, titratable acidity, respiration, and ethylene production were measured at harvest, and subsequent storage behavior and sensory quality of the fruit were evaluated. The results indicate that a combination of initial soluble solids content at harvest, and flesh firmness, similar to the maturity index for pear, seems promising as a maturity index for kiwifruit.
SYNOPSIS The susceptibility of the avocado to both vibration and impaction as influenced by culti... more SYNOPSIS The susceptibility of the avocado to both vibration and impaction as influenced by cultivar, maturity and flesh firmness was studied. Emphasis was placed on the Hass variety since it comprises about 70 per cent of the total California acreage. External vibration injury (1,1 x g for 20, 40 or 60 min) is easily discernible in Fuerte, Pinkerton and early-season Hass fruit as surface discolouration. As the Hass variety darkens either during ripening or with maturity, the external symptoms of injury are masked. As flesh firmness decreases during ripening ( 6,8 kgf), prior to extensive softening, no appreciable damage is observed as a result of impaction (23, 46 or 92 cm). As flesh softening occurs, bruising due to impaction increases. Bruising is characterised by flesh discolouration sometimes extending into the seed cavity in soft fruit and occurred in all evaluated varieties.
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