Key Techniques for Greenhouse Grape Cultivation Management and Control of the Grape Tiger Longhorn Borer

Greenhouse grapes come to market early, generally at least 1-2 months earlier, supplementing the off-season fruit supply, and fetch a high unit price on the market, making them relatively profitable. So how do you cultivate and manage greenhouse grapes? What are the key techniques for controlling the grape tiger longhorn borer pest?

I. How to cultivate and manage greenhouse grapes?

1. Variety selection

Through trials across the country, the varieties suitable for greenhouse cultivation include Jingya, Jingxiu, Fenghuang 51, Jingyou, Chana and Jufeng (Kyoho). The common characteristics of these varieties are a short dormancy period, strong productivity, tolerance to high temperatures, tolerance to storage and transport, a short fruit development period, early ripening, moderate growth, disease resistance and ease of management.

2. Planting and orchard establishment

Use vigorous one-year-old cuttings, requiring more than 20 main and lateral roots, root length over 15 cm, stem diameter over 1 cm, and 4-6 plump buds. Planting density varies with variety, site conditions, training system and seedling resources. Generally, for trellis training, the row spacing is 1.2-1.5 m × 0.5 m, with about 1000 plants per mu. After the row and plant spacing is determined, trenches must be dug and the soil improved, with sufficient base fertilizer applied, and high-standard orchard establishment carried out to obtain high returns. Generally, planting trenches 50-80 cm deep and 50-80 cm wide are dug, with 4000-5000 kg of farmyard manure applied per mu. When digging the trenches, keep topsoil and subsoil separate, then backfill the topsoil first, followed by the subsoil, incorporating organic fertilizer in layers. The planting time and method are the same as for conventional tree planting.

3. Fertilizer and water management

After the seedlings survive, promptly apply quick-acting nitrogen fertilizer to promote growth. In autumn, apply more phosphorus and potassium fertilizer, and also spray fertilizer on the leaves, taking care to apply small amounts frequently. Starting in September, apply base fertilizer early. During the growing season, irrigate promptly in case of drought, and pay attention to drainage during the rainy season.

4. Building and covering the greenhouse

In September-October, build a greenhouse over a one-year-old densely planted vineyard. It can be harvested and marketed in early summer of the second year. In northern regions, a solar greenhouse is used, with an east-west slightly arched style and a back wall on the north side. The span is 7-9 m, and the length is 50-70 m. The back wall and the two gable walls are made of brick-earth structure, 50-80 cm thick; the back wall is 2-2.5 m high, the ridge height is about 3 m, and the distance from the back wall is 1.2-1.5 m.

The supports are reinforced concrete columns, the framing material is bamboo and wood, and the back is covered with 50 cm thick corn stalks, compacted with soil. In the Yangtze River basin, a plastic greenhouse is used, arch-shaped in a north-south direction, with a span of 5-7 m, a length of 30-50 m and a height of 3 m. Bamboo and wood, cement precast components, or steel pipes can be used as the frame. The greenhouse film uses a drip-free film with good light transmission and insulation, with the edges pressed into the soil.

In the solar greenhouse, a ventilation opening 0.8 × 0.5 m in length and width is left every 5 m, covered with greenhouse film or a hand-pulled straw curtain. At that time, cover the greenhouse with film, replacing it with new film every year. Grapes begin dormancy when they shed their leaves, generally completing natural dormancy in about 2 months. After completing natural dormancy, the greenhouse can still be covered and warmed. From north to south, grapes begin to shed leaves from late October to late November, with the corresponding greenhouse covering time from mid-to-late December to late January.

5. Temperature management inside the greenhouse

Generally, before warming, irrigate thoroughly along the rows once, cover with plastic film to conserve moisture, and then raise the temperature. The temperature inside the greenhouse should be raised gradually, and can be divided into 5 stages.

Before bud break: daytime temperature 15-18°C, nighttime 5-6°C. From bud break to before flowering: daytime 18-20°C, nighttime 6-7°C. During flowering, the temperature is slightly higher: daytime 25-28°C, nighttime 8-10°C. From petal fall to fruit enlargement stage: daytime 25-30°C, nighttime 15-18°C. From fruit coloring to harvest stage: daytime no higher than 30°C, nighttime around 15°C, widening the day-night temperature difference to promote fruit coloring and sugar accumulation.

6. Humidity control inside the greenhouse

For the air humidity inside the greenhouse, from covering to bud break, the relative humidity should be controlled at around 90%, from bud break to before flowering at 60-70%, from flowering to fruit enlargement stage at 50-60%, and thereafter until harvest at 50%. For soil moisture, from greenhouse covering to harvest, the soil relative water-holding capacity should be maintained at 60-80%. During different phenological periods, water demand is greater at the bud break and fruit enlargement stages, and it should preferably be controlled in the 70-80% range. During fruit growth and development, try to avoid excessive fluctuations in soil water content to prevent fruit cracking.

7. Training and pruning

In the first year, winter pruning is done by heading the trunk at 80 cm. It then sprouts 5-7 fruiting canes; except for the lowest shoot, which is kept as a reserve cane without any fruit cluster, each of the others keeps one fruit cluster. Weak shoots keep no fruit cluster, and the secondary cluster and 1/3-1/5 of the cluster tip are pinched off at the same time. After fruit set, trim the cluster, thinning small berries and excess berries; keep 50-60 berries per cluster, while the large-fruited Jufeng (Kyoho) needs only 40, averaging 400 g per cluster, about 2 kg per plant, and the per-mu yield should preferably be controlled at 2000-2500 kg; if the yield is too high, quality will decline. In the second year, winter pruning is done by cutting back 1 cm above the reserve cane, and the reserve cane is pruned as a medium-long cane to serve as the fruiting mother cane for the next year. The third year follows the same pattern, with fruiting canes renewed each year to keep the fruiting position stable.

II. Key techniques for controlling the grape tiger longhorn borer pest

1. Living habits of the grape tiger longhorn borer

The grape tiger longhorn borer has one generation per year, overwintering as young larvae inside the canes. After May, the overwintering larvae in the canes begin activity and continue boring and causing damage. They begin pupating in July and emerge as adults in August. Adults lay eggs in the crevices of bud scales or on buds, leaf surfaces and canes. The egg stage lasts about 5 days, and newly hatched larvae mostly bore into the canes near the buds. They first damage the area under the bark, then gradually bore into the xylem until entering a dormant state.

2. Damage symptoms of the grape tiger longhorn borer

It mainly damages canes as larvae. The damaged bark becomes slightly raised and black, and the frass is deposited inside the tunnel, with no frass outside the bark, so it is not easily noticed. After the larvae bore into the xylem, the damaged part breaks easily in the wind. Adults can also bite and feed on young grape canes, young buds and leaves.

3. Control methods for the grape tiger longhorn borer

(1) Manual control: This should be carried out after grape leaf fall in late autumn or when trellising in early spring. Carefully check the canes for any blackened areas; once found, cut off the blackened canes and burn them. For large canes that must be kept, pierce them with iron wire or insert cotton balls soaked in dichlorvos to poison the pests. If a fruiting cane does not sprout or wilts shortly after sprouting, it may be an infested cane and can also be treated as above. Adults have poor migration ability, so manual capture on early mornings when the dew has not yet dried during the adult emergence and egg-laying period is very effective.

(2) Chemical control: When the infestation is heavy, spray 1000-fold fenitrothion solution or 3000-fold fenvalerate solution during the peak adult period, or plug the bore holes with cotton dipped in 200-fold dichlorvos solution. During the adult egg-laying period, spray 500-fold 90% trichlorfon solution for control.