Grapevine Damaging Downy Mildew 14/08/2021

P.h D. Nguyen Minh Tuyen.

    Grapes are one of the crops with high economic value. Grapes are being favored by society and widely consumed in the form of fresh fruit. However, in the process of grape production, farmers often face many pests and diseases. In particular, downy mildew is one of the most dangerous diseases of grapes. Downy mildew can cause crop failure, increase costs and hinder grape production for farmers.

* Symptoms and harms:

The disease usually affects the young parts of the plant, then spreads to the part is neither old nor young. In humid conditions, the affected part is covered with a white fungus, especially the  cluster of flower buds, and the underside of the leaves. On leaves, lesions have an irregular shape, at first slightly yellowish, then gradually turning brown. The most dangerous is on flower buds, the disease often attacks very early when flower buds have just appeared. The disease can damage  all cluster of flower buds and cause major yield losses.

* Pathogens and suitable conditions for development:

 +Disease caused by the Plasmopara viticola fungus.

 

+ Suitable conditions for growth:

- The cleaning of the remnants of the previous crop was not good, the trellis was not suitable, the garden was shaded by other trees etc ...

- Planting with high density, cutting to create too thick canopy, unbalanced fertilization, excess nitrogen, lack of organic and micro-fertilizers, dense vineyards.

- Poor water management, often wet gardening.

- The garden is in the flower bud stage, prolonged rainy or foggy weather, high air humidity, little sunshine are optimal conditions for disease development etc

Effectively preventive measures:

- Make appropriate trellis, planting density and create a canopy to ensure ventilation.

- Cleaning and destroying the remains of the previous crop, clearing large trees to shade around the garden.

- Prune ventilation, do not leave the garden dense, to reduce the humidity in the garden and facilitate later product spraying.

- Raise high beds and water appropriately so that the garden is not wet often.

- Balanced fertilizer application, with enough organic matter, supplemented with semi-macro and trace elements to help increase the resistance of plants such as TANO-601 foliar fertilizer before and during the fruiting flowering period.

- Before, during and after the cluster of  flower buds appear, or when the weather conditions are much rainy, cloudy, less sunny, more foggy, and humid, it is necessary to alternate prevention with the following products: DIPOMATE 430SC, or PYLACOL 700WP, or CLEARNER 75WP

- Should spray 2-3 times 3-5 days apart, depending on the conditions of the garden and weather.

 

Same item

To prevent, in addition to plowing and burying weed seeds, collecting weed stalks and stumps left after tilling the land to burn, not letting weeds produce seeds in production fields, etc., the use of chemical products is still a measure. optimal because of its ability to thoroughly kill weeds, reduce labor and take advantage of more time than manual weeding.To prepare for the coming Summer-Autumn rice crop, we would like to introduce to you a very new product of Saigon Plant Protection Joint Stock Company, which is Butoxim 5GR. This is a granular product used for spreading by Saigon Plant Protection Joint Stock Company in research, production and distribution.

 

 Miner has the scientific name Phyllocnistis citrella Staint., family Phyllocnistidae, order Lepidoptera. The  miner occurs in many countries in the tropics and subtropics. The main host of the miner is the citrus family - Rutaceae. In addition, the miner also attacks mangosteen and some other plants.

 

Adult is a small planthopper, with a body 2-3 mm long, the whole body is ash gray, slightly greenish, the wings are opaque with many small brown spots.Eggs are oval, 0.3 mm long, have a pointed end and are attached directly to the leaf surface, leaf axils.Larvae are very small, oval in shape, newly hatched are bright yellow. Age 2 and age 3 are in green. Age 4 and age 5 are golden brown and 2 small wing sprouts.

 

Green bugs specialize in the fruit of citrus groups (oranges, tangerines, lemons, grapefruits, kumquats...), some people call them orange bugs, or orange suckers. Their scientific name is Rhynchocoris poseidon or Rhynchocoris humeralis.

 In Vietnam, yellow leaf curl disease is very common on papaya trees, especially the disease is often severe in areas of high and continuous planting, areas with hot and arid climates. The disease has significantly reduced the yield and quality of papaya. Gardens that are infected early when the plants are young may not yield. However, up to now, many gardeners still do not know the cause and how to fix it.

 

 Spider mites are common pests on citrus trees, especially in hot and dry climates that are suitable for spiders to grow and cause severe damage.The group of harmful spiders is usually very small in size, unlike the natural enemy spiders.Spiders have a very short life cycle, high reproductive ability, create many generations in a year, so it is easy to break out into epidemics in a short time.

 

 This group includes species that are generally very small in size, causing damage by sucking plant sap (on leaves, fruits, branches, stems).

There are many species of mealybugs present on the group of Oranges,Tangerines,Grapefruits and Lemons (Citrus), which can be divided into 2 groups:

+ Group of sticky mealybugs with common varieties such as Lepidosaphes, Aonidiella, Coccus and Saissetia.

+ Group of flower mealybugs with common genera and species such as Pseudococcus, Planococcus and Icerya purchasi.

Dry branches and berries disease often appear to be common damage on coffee gardens during the rainy season. The disease causes death of branchs, dry fruit, severely affects the canopy structure and coffee yield if not paid attention to prevention.

  

 Pink disease commonly causes diseases on rubber plantations in the rainy season, especially on garden from 4-8 years old. This year, rubber has to go through a period of severe drought, weakening the tree, so now in tnshe rainy season it is easy to get infected. Therefore, it is necessary to pay attention to good management to avoid affecting the garden.

In recent years, the area of citrus has been expanded because it is a fruit tree with high economic efficiency. However, in order to sell at a high price, not only in quality but consumers also require the external beauty of the fruit, so pest management on citrus is a matter of great concern to farmers. The hot season is a favorable condition for thrips to develop and cause damage, affecting the commercial value of fruit.

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