Plant protection of cucumbers against diseases and cultivation techniques for cucurbit crops in a greenhouse

Cucumber disease control in greenhouses

Under protected ground conditions, cucumbers are frequently affected by bacteriosis and a complex of spot diseases. Bacteriosis, or angular leaf spot, manifests as oily spots on the leaves, which eventually darken, dry out, and fall out. With this disease, characteristic watery spots form on the fruits, reducing their commercial quality. To contain the development of the infection, the agronomist must observe crop rotation and remove affected fruits from the plantation in a timely manner.

To prevent bacteriosis, plantings are regularly sprayed with 1% Bordeaux mixture at intervals of 10–12 days. Olive spot, ascochyta blight, and anthracnose are also capable of causing serious damage to the harvest in protected ground. The primary method of plant protection against these pathogens is strict maintenance of the optimal temperature and air humidity.

Cultivation techniques for zucchini, pattypan squash, and pumpkin

Zucchini and pattypan squash are more cold-resistant than cucumber and less demanding in terms of light compared to pumpkin. These crops are grown both by direct sowing of seed into the soil and via 25–30-day-old containerized transplants. When planting transplants at a permanent location, it is important to adhere to a planting scheme of 70x70 cm.

To accelerate root growth and general plant development, the soil is mulched with film, including used material. Cross-shaped cuts are made on the cut pieces of film, into which the transplants are planted, burying them up to the cotyledonous leaves. When growing under small covers, the film must be removed during flowering to allow access for pollinating insects, and in cases of heavy crowding, 2–3 leaves are removed from each bush.

• Optimal growth temperature — 20–25 °С
• Age of transplants for planting — 25–30 days
• Planting scheme for zucchini — 70х70 cm
• Planting scheme for pumpkin — 100х100 cm
• Daylight length for pumpkin — 12–14 hours

Pumpkin is a light-loving short-day crop that tolerates drought well due to its powerful root system, but stops growing at temperatures below 10 °С. For its cultivation, loose, humus-rich soils are selected. Before sowing, it is essential to perform a selection of large seed and conduct their preliminary treatment.

To increase cold resistance, pumpkin seed are subjected to temperature hardening according to a specific scheme.

1. Moisten the pumpkin seed.
2. After 2–3 hours, place them in conditions with a temperature of 0–5 °С for 18 hours.
3. Move the seed to a warm environment with a temperature of 15–18 °С for 6 hours.
4. Repeat this cycle for 5–6 days.

Since pumpkin does not tolerate transplanting well, transplants are grown individually in pots sized 8x8 or 10x10 cm. In protected ground, until emergence, a temperature of 18–25 °С is maintained, then for one week it is lowered to 12–16 °С, and ventilation is increased. Subsequently, the following regime is established: on sunny days 24–26 °С, on cloudy days 20–22 °С, at night 15–18 °С, with mandatory protection against frosts.

Pumpkin transplants are watered as needed and fertilized twice to strengthen the root system. The first top dressing is carried out on the 10–12th day after emergence with a mullein solution at a ratio of 1:10. After another 10 days, a mineral complex is applied, consisting of 15 g of ammonium nitrate, 30 g of superphosphate, and 20 g of potassium sulfate per 10 l of water.

In open ground, pumpkin is placed after any preceding crops, except for related cucurbits. In the autumn, 6–8 kg of humus per 1 m² is applied under ploughing, and in the spring — mineral fertilizers: 10 g of ammonium nitrate, 30–40 g of superphosphate, and 20 g of potassium chloride per 1 m². Transplants are planted into holes according to a 100x100 cm scheme, watered, and equipped with film covers 80–90 cm high with a distance between the ends of the hoops of at least 100 cm.

During the period of growing pumpkin under film, the covers must be ventilated; otherwise, in damp, stagnant air, the flowers will not be pollinated and the fruit sets will rot. At the permanent location, plants are fertilized 2 weeks after planting with 1:6 mullein or ammonium nitrate (20 g per 10 l of water) at a rate of 7–8 l per 1 m². The second top dressing is given 14–15 days after the first, using 15–20 g of ammonium nitrate, 20–30 g of superphosphate, and 10–20 g of potassium sulfate per 10 l of water.

Agrotechnics of watermelon in hotbeds

Watermelon is a light-loving and heat-loving crop, which in the conditions of the middle zone is grown mainly in hotbeds. To create an optimal microclimate, hotbeds are filled with biofuel and additionally insulated with a layer of film. Obtaining a stable harvest requires precise adherence to the temperature regime at all stages of the growing season.

• Minimum temperature for seed germination — 18 °C
• Optimal growth temperature — 18–32 °C
• Diameter of seedling pots — 8–10 cm
• Planting pattern for the permanent location — 100x150 cm or 150x150 cm

Preparation for sowing begins with thorough manual calibration of seeds, selecting the largest ones for the work. To protect future seedlings from pathogens and stimulate their growth, the seed material undergoes sequential treatment. The entire preparation process includes several mandatory stages.

1. Disinfect the seeds for 30 minutes in a solution of potassium permanganate (10 g of the preparation per 10 l of water).
2. Soak the seeds for 12 hours in a solution of boric acid (0.2 g per 1 l of water) or baking soda (10 g per 1 l of water).
3. Rinse the seeds with clean water after soaking and send them for germination.
4. Plant the sprouted seeds in pots with a diameter of 8–10 cm when the sprouts reach a length of 3–4 mm.

Transplants are best grown indoors with good lighting and regular ventilation. The air temperature is maintained at 19 °C, but not higher than 27 °C. Seedlings must be protected from drafts, sudden cold snaps, and spring frosts.

For active growth, formation of strong vines, and high yield, the plants require regular top dressing. During the growing process, organic and mineral components are combined. Exact dosages and phases of fertilizer application are presented in the table.

After transplanting into the hotbed, watermelon vines are directed in a circle as they develop, and then laid out across the bed and pinned to the soil. Plant formation begins when the fruit set reaches the size of a walnut. 4 to 6 fruit sets are left on one vine, pinching the shoot above the fifth leaf above the fruit. All other vines, especially fruitless lateral shoots, are completely pruned.

It is recommended to harvest in hotbeds selectively, as the fruits reach the required condition. The ripeness of a watermelon is determined by the drying tendril in the leaf axil and a dull sound when tapping the rind with a fingernail. Fruits that fully ripen on the vine possess the best taste qualities.