Cold treatment of “Hass” avocado (Persea americana (Lauraceae)) infested by Thaumatotibia leucotreta (Lepidoptera: Tortricidae) as an additional component of a systems approach

Thaumatotibia leucotreta, known as the false codling moth, is a pest of citrus and other crops in sub-Saharan Africa. As it is endemic to this region and as South Africa exports most of its citrus around the world, T. leucotreta has phytosanitary status for most markets. This means that there is zero tolerance for any infestation with live larvae in the market. Consequently, control measures prior to exporting must be exemplary. Certain markets require a standalone postharvest disinfestation treatment for T. leucotreta. However, the European Union accepts a systems approach, consisting of three measures and numerous components within these measures. Although effective preharvest control measures are important under all circumstances, they are most critical where a standalone postharvest disinfestation treatment is not applied, such as within a systems approach. Conventional wisdom may lead a belief that effective chemical control tools are imperative to achieve this end. However, we demonstrate that it is possible to effectively control T. leucotreta to a level acceptable for a phytosanitary market, using only biological control tools. This includes parasitoids, predators, microbial control, semiochemicals, and sterile insects. Simultaneously, on-farm and environmental safety is improved and compliance with the increasing stringency of chemical residue requirements imposed by markets is achieved.

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Note. Effect of Storage Temperature on the Shelf Life of Hass Avocado (Persea Americana)

Food Science and Technology International ◽

10.1177/1082013204043763 ◽

2004 ◽

Vol 10 (2) ◽

pp. 73-77 ◽

Cited By ~ 15

Author(s):

K. Perez ◽

J. Mercado ◽

H. Soto-Valdez

Keyword(s):

Weight Loss ◽

Shelf Life ◽

Respiration Rate ◽

Ethylene Production ◽

Storage Temperature ◽

Persea Americana ◽

Co2 Production ◽

Hass Avocado ◽

Storage Temperatures

The effect of storage temperature on the shelf life, weight loss, respiration rate and ethylene production of Hass avocado (Persea americana Mill) was studied. Two batches of green mature avocado fruits, classified as ‘‘super extra’’ were stored at 10 and 20 C (first batch) and at 7 and 25 C (second batch). The avocado shelf lives were 22, 8, 32 and 6 days at 10, 20, 7 and 25 C, respectively. Based on the data of the first assay Q10 was calculated as 2.75, with this value the predicted shelf life at 7 and 25 C were 29.8 and 4.8 days, respectively. That meant shelf life was underestimated 7 and 20% at 7 and 25 C, respectively. Weight loss was linear at both the storage temperatures, it was 4.3% in fruits at 20 C for 8 days and 3.0% at 10 C for 22 days. The maximum CO2 production at 20 C was reached during the second day of storage, while at 10 C it was reached at the 17th day (176.17 15.98 and 74.73 7.32 mL/kg h, respectively). The maximum ethylene production at 20 C was reached the second day of storage, and at 10 C the 6th day (239.06 54.55 and 28.00 8.12 mL/kg h, respectively).

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Characterization and Pathogenicity of Botryosphaeriaceae Species Obtained from Avocado Trees with Branch Canker and Dieback and from Avocado Fruit with Stem End Rot in Chile

Plant Disease ◽

10.1094/pdis-07-18-1131-re ◽

2019 ◽

Vol 103 (5) ◽

pp. 996-1005 ◽

Cited By ~ 8

Author(s):

Ana L. Valencia ◽

Pilar M. Gil ◽

Bernardo A. Latorre ◽

I. Marlene Rosales

Keyword(s):

Vascular System ◽

Persea Americana ◽

Effective Control ◽

Future Research ◽

Severe Drought ◽

Internal Transcribed Spacer Region ◽

Avocado Fruit ◽

Hass Avocado ◽

Botryosphaeriaceae Species ◽

Branch Canker

Several species of the Botryosphaeriaceae family have been associated with branch canker, dieback, and stem end rot in avocado (Persea americana Mill.). In Chile, the incidence of diseases affecting the avocado tree increased from 2011 to 2016, which coincided with a severe drought that affected avocado production. Moreover, distant countries importing avocados from Chile also reported an increase of stem end rot of ripe avocados. Therefore, the aims of this study were to identify the pathogen species associated with branch canker, dieback, and stem end rot of avocado in Chile and to study their pathogenicity. This study was conducted between 2015 and 2016 in ‘Hass’ avocado orchards located in the main avocado-producing regions in Chile. A diverse collection of fungal species was recovered from both necrotic woody tissue and necrotic tissue on harvested ripe fruit. On the basis of morphology and phylogenetic analyses of the internal transcribed spacer region (ITS1-5.8S-ITS2) and the translation elongation factor 1-α (TEF1-α) gene, eight species in the Botryosphaeriaceae family were identified: Diplodia mutila, D. pseudoseriata, D. seriata, Dothiorella iberica, Lasiodiplodia theobromae, Neofusicoccum australe, N. nonquaesitum, and N. parvum. For each of these species, pathogenicity studies were conducted on 1-year-old healthy Hass avocado plants. All isolates produced brown gum exudate and caused necrosis in the vascular system 3 weeks after inoculation. N. nonquaesitum, N. parvum, and D. pseudoseriata were the most virulent species. Necrotic lesions and cavities with white mycelia near the peduncle union were observed on Hass avocado fruit inoculated postharvest. L. theobromae, N. australe, and N. parvum were significantly more virulent than the other tested species in the Botryosphaeriaceae family. This study identified and characterized the pathogenicity of Botryosphaeriaceae species in Chile, which will prove useful to future research on these pathogens directed at establishing effective control strategies in avocado.

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Optimal Nutrient Concentration Ranges of ‘Hass’ Avocado Cauliflower Stage Inflorescences—Potential Diagnostic Tool to Optimize Tree Nutrient Status and Increase Yield

HortScience ◽

10.21273/hortsci12437-17 ◽

2017 ◽

Vol 52 (12) ◽

pp. 1707-1715 ◽

Cited By ~ 2

Author(s):

Salvatore Campisi-Pinto ◽

Yusheng Zheng ◽

Philippe E. Rolshausen ◽

David E. Crowley ◽

Ben Faber ◽

...

Keyword(s):

Nutrient Concentration ◽

Fruit Set ◽

Fruit Size ◽

Nutrient Status ◽

Persea Americana ◽

Nutrient Concentrations ◽

Full Bloom ◽

Nutrient Analysis ◽

Tree Phenology ◽

Hass Avocado

Optimizing ‘Hass’ avocado (Persea americana Mill.) tree nutrient status is essential for maximizing productivity. Leaf nutrient analysis is used to guide avocado fertilization to maintain tree nutrition. The goal of this research was to identify a ‘Hass’ avocado tissue with nutrient concentrations predictive of yields greater than 40 kg of fruit per tree. This threshold was specified to assist the California avocado industry to increase yields to ≈11,200 kg·ha−1. Nutrient concentrations of cauliflower stage inflorescences (CSI) collected in March proved better predictors of yield than inflorescences collected at full bloom (FBI) in April, fruit pedicels (FP) collected at five different stages of avocado tree phenology from the end of fruit set in June through April the following spring when mature fruit enter a second period of exponential growth, or 6-month-old spring flush leaves (LF) from nonbearing vegetative shoots collected in September (California avocado industry standard). For CSI tissue, concentrations of seven nutrients, nitrogen (N), phosphorus (P), potassium (K), magnesium (Mg), sulfur (S), zinc (Zn), and copper (Cu) were predictive of trees producing greater than 40 kg of fruit annually. Conditional quantile sampling and frequency analysis were used to identify optimum nutrient concentration ranges (ONCR) for each nutrient. Optimum ratios between nutrient concentrations and yields greater than 40 kg per tree were also derived. The high nutrient concentrations characterizing CSI tissue suggest current fertilization practices (timing or amounts) might be causing nutrient imbalances at this stage of avocado tree phenology that are limiting productivity, a possibility that warrants further investigation. Because CSI samples can be collected 4–6 weeks before full bloom, nutritional problems can be addressed before they affect flower retention and fruit set to increase current crop yield, fruit size, and quality. Thus, CSI nutrient analysis warrants further research as a potential supplemental or alternative tool for diagnosing ‘Hass’ avocado tree nutrient status and increasing yield.

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Cold treatment enhances low‐temperature flight performance in false codling moth, Thaumatotibia leucotreta (Lepidoptera: Tortricidae)

Agricultural and Forest Entomology ◽

10.1111/afe.12326 ◽

2019 ◽

Vol 21 (2) ◽

pp. 243-251

Author(s):

Nevill Boersma ◽

Leigh Boardman ◽

Martin Gilbert ◽

John S. Terblanche

Keyword(s):

Low Temperature ◽

Cold Treatment ◽

Codling Moth ◽

Flight Performance ◽

Thaumatotibia Leucotreta ◽

False Codling Moth

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Avoiding Chilling Damage in ‘Hass’ Avocado Fruit by Controlled Atmosphere Storage at Higher Temperature

HortScience ◽

10.21273/hortsci12070-17 ◽

2017 ◽

Vol 52 (8) ◽

pp. 1107-1110 ◽

Cited By ~ 1

Author(s):

Jeremy Burdon ◽

David Billing ◽

Paul Pidakala

Keyword(s):

Skin Color ◽

Storage Temperature ◽

Persea Americana ◽

Controlled Atmosphere ◽

Storage Duration ◽

Avocado Fruit ◽

Significant Difference ◽

Chilling Damage ◽

Hass Avocado ◽

Atmosphere Storage

Sea-freight distribution of ‘Hass’ avocado (Persea americana) is by refrigerated containers, sometimes supplemented by controlled atmosphere (CA). With both refrigeration and CA prolonging the storage life of the fruit, there is a question as to whether the technologies can be traded. That is, by using CA at warmer temperatures to extend storage without the risk of chilling damage. In this project, the potential to avoid chilling damage by storing fruit at 7 °C in 2% O2/2% CO2 CA instead of 5 °C in 2% O2/2% CO2 CA or air has been investigated for fruit stored for 4 or 6 weeks. Increasing the storage temperature from 5 °C to 7 °C did not affect the quality of fruit immediately out of CA storage, with no significant difference in skin color, firmness, or skin disorders. Both CA storage regimes, at 5 °C or 7 °C, resulted in better fruit quality than for fruit that had been stored in air at 5 °C. Overall, CA at 7 °C was less effective at retarding the progression of ripening in storage than CA at 5 °C, although after 4 weeks of storage, fruit from both CA regimes took longer to ripen than the air-stored fruit. After 6 weeks of storage, there was no difference in ripening time between fruit that had been stored in CA at 7 °C or in air at 5 °C, with fruit that had been in CA at 5 °C still taking longest to ripen. However, the incidence of diffuse flesh discoloration (DFD) in the air-stored fruit was high compared with that in fruit from CA at 7 °C or 5 °C. The main negative aspect to storing fruit in CA at 7 °C rather than at 5 °C was the higher incidence of rots in ripe fruit. While it was lower in the air-stored fruit, the incidence in fruit that had been stored in CA at 7 °C tended to be higher than that of the fruit stored in CA at 5 °C. It therefore appears that the potential for using CA at slightly higher temperatures to avoid chilling damage rests on the storage duration required and the risk of rots in the fruit.

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