Guides of Postharvest diseases and defects evaluation

Prepared by Tuan Minh NGUYEN, PhD

Dept. of Post-harvest Technology and Processing, Fruit and Vegetable Research Institute- FAVRI

JAF- Awardee Research Project funded by the Australian Centre for International Agricultural Research

ANTHRACNOSE

Cause: The fungus Colletotrichum gloeosporioides.

Symptoms: dark spots that enlarge to irregular, black areas at ripe.

Control: After harvesting, orchard hygiene (weed removal, diseased dead branches, and pruning canopy for sunlight direction). Pesticide spraying (Carbenzim 500FL, Saipora 350SC) at 2 weeks before flowering, at fruit setting and at 4 weeks before harvest. For harvested fruit, use 0.1% Carbenzim 500FL or 0.55 mL/L Sportak®or 1.8ml/L Tecto (Thiabendazole) for 30 s.

 

 

STEM-END ROT

Cause: Several fungi including Dothiorella spp.,

Phomposis persea and Lasiodiplodia theobromae.

Symptoms: Only develop after harvest. Stem-end rotting spread near the stem part. The rot has dark and soft area.

Control: Do not use the diseased plants for propagation. Disinfect, clean grafting tools. Orchard hygiene (removal of dead flower parts, leaves, and twigs) is done. Harvesting fruit in dry days, avoid bruising fruit. After harvesting can dip fruit in 0.1% Benlate (benomyl)or 0.55 mL/L Sportak (prochloraz).

 

SEED CAVITY BROWNING

Cause: Poor handling after harvest (picking, packing, marketing) or cool storage of fruit harvested from boron-deficient trees.

Symptoms: Damage appears as discrete brown areas in the seed cavity. Symptoms develop only at ripe.

Prevention: Apply borax to the ground under the tree or mixing it to water and spraying it on the ground. Handle fruit carefully. Avoiding drop fruit > 20cm for hard green fruit;> 5cm for sprung to ripe fruit.

 

 

 UNEVEN RIPENING FLESH

Cause:Excess moisture close to the time of fruit maturity due to heavy rain.

Symptoms: Affected fruit appear normal externally, but sections of the fruit fail to ripen, remaining firm and rubbery.

Prevention:Draining system to minimize the effect of heavy rain on the root system.
 
 LENTICEL DISCOLOURATION

Causes:Stress on lenticels (water contact, chemical and mechanical damage).

Symptoms: Dark mall spots on the skin.

Prevetion:Coating, suitable storage condition (85-90% RH)
 
 WATER LOSS

Causes:Moisture loss during storage and ripening.

Symptoms: Witheredskin.

Prevetion:Coating, suitable storage condition (85-90% RH)
 

Vietnam's lychee farmers bemoan slumping prices

BAC GIANG, Vietnam: Hundreds of lychee farmers sorted and graded huge piles of the tropical fruit at a busy wholesale market in northern Vietnam yesterday, but many bemoaned slumping prices as foreign traders were held up in quarantine. After mounting an aggressive response to the coronavirus pandemic, life in the country is back to relative normality and workers clustered together mask-free at dawn in Bac Giang province, their motorbikes fitted with baskets overflowing with the sweet fruit. The communist nation usually exports around 100,000 tonnes of fresh lychees worth more than $30 million -- mostly to China but to Japan, Australia and. Detail

Vietnam seeks to export fresh fruits, vegetables to Thailand

Vietnamese fruit and vegetable exporters are seeking to make inroads into Thailand amidst the COVID-19 pandemic. According to the Vietnam Fruit & Vegetable Association (VinaFruit), exports to the US, Thailand and Africa saw positive signs last year. Vietnam exported 74.94 million USD worth of fruits and vegetables to Thailand in 2019, up 66.3 percent compared to the previous year. Secretary General of VinaFruit Dang Phuc Nguyen suggested that the Ministry of Agriculture and Rural Development should negotiate with the Thai Ministry of Agriculture and Cooperatives to balance trade for fruits and vegetables because Vietnam has long been running a trade deficit for farm. Detail

Bac Giang: More lychee to be grown for export to Japan

The northern province of Bac Giang has granted cultivation area codes to many orchards growing lychee for export to Japan this year, according to the provincial Department of Agriculture and Rural Development. Nineteen cultivation area codes have been issued to date for 103 ha of lychee in the province to be exported to the country, primarily in the communes of Hong Giang, Nam Duong, Tan Son, Quy Son, Giap Son, and Ho Dap in Luc Ngan district and Phuc Hoa commune in Tan Yen district. The province is actively directing lychee growers in following standardised production processes while encouraging businesses to buy. Detail

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