Causes and Control Methods of Deformed Fruit in Zucchini

Zucchini is grown in Shandong, Shanxi, Henan, Hebei and other places, and is a type of pumpkin. Also known as eggplant melon, bear (male) melon, white melon, small melon, foreign melon, horn melon, xun melon, etc. Native to India, it is grown in both southern and northern China. Zucchini has the effects of clearing heat and promoting diuresis, relieving restlessness and quenching thirst, moistening the lungs and stopping cough, and reducing swelling and dispersing masses.

Morphological characteristics of zucchini

Zucchini is an annual trailing herbaceous plant, with three major lines: dwarf, semi-trailing and trailing. Most varieties have obvious main vine dominance, with few and weak side vines. The stem is thick and robust, cylindrical, with white short bristles. The stem has angular grooves, with short bristles and translucent rough hairs.

Leaves

The petiole is thick and robust, covered with short bristles, 6-9 cm long. The leaf blade is hard in texture, upright, triangular or ovate-triangular, with a sharply pointed tip, irregular sharp teeth on the margin, a heart-shaped base, and a semicircular sinus, 0.5-1 cm deep and 3-4 cm wide; the upper surface is dark green, the lower surface is lighter in color, the veins are slightly raised on the back, and both sides have rough hairs. The tendrils are slightly thick and robust, with soft hairs, and are much branched.

Flowers

Monoecious. Male flowers solitary; the pedicel is thick and robust, angular, 3-6 cm long, covered with yellowish-brown short bristles; the calyx tube has obvious 5 angles, and the calyx lobes are linear-lanceolate; the corolla is yellow, often gradually narrowed toward the base and bell-shaped, 5 cm long and 3 cm in diameter, split to near the middle, with lobes upright or slightly spreading, with sharply pointed tips; there are 3 stamens, the filaments are 15 mm long, and the anthers are coherent, 10 mm long.

Deformed fruit of zucchini not only affects the overall appearance of zucchini, but also causes a decline in zucchini planting benefits, so farmers must pay attention to deformed fruit of zucchini. Below we will introduce the causes of deformed fruit formation in zucchini and how to control it.

The reasons for deformed fruit in zucchini are as follows:

1. Insufficient water and fertilizer. Insufficiency in the early fruit-setting stage easily forms pointed-tip fruit, insufficiency in the middle stage easily forms thin-waist fruit, and insufficiency in the late stage easily forms slender crooked-stem fruit. However, too much fertilizer and water in the middle stage easily forms big-belly fruit.

2. Poor pollination, with uneven distribution of pollen, causes the insufficiently pollinated parts to appear sunken.

3. Too high or too low temperature will affect photosynthetic efficiency, making the nutrients produced insufficient and inhibiting fruit development.

4. The female flower itself is defective or a bisexual flower forms fruit, causing deformity.

Control methods for deformed fruit in zucchini:

In order to promote early-maturing cultivation of zucchini to bear more high-quality fruit, in cultivation measures it is necessary to create a good ecological environment and improve management techniques.

1. Meet fertilizer and water requirements. Zucchini requires more fertilizer, has strong fertilizer absorption capacity, and is relatively drought-tolerant, but the fruit expansion stage requires more water, so the soil must be kept moist. Therefore, first, apply sufficient base fertilizer; second, apply timely topdressing with nitrogen and potassium combined, and topdress once after each batch of melons is harvested. In the base fertilizer, apply 5000 kg of high-quality farmyard manure, 300 kg of cake fertilizer, 100 kg of phosphate fertilizer, and 50 kg of potassium fertilizer per mu, while appropriately applying zinc fertilizer and magnesium fertilizer. Field moisture should mainly be controlled by drying in the early stage, and moist management should be maintained during the fruiting stage.

2. Pay attention to regulating temperature. Early-maturing cultivation mostly uses plastic film greenhouses with small sheds inside to increase and maintain temperature. The suitable temperature range for zucchini is 15--38°C, and the optimum temperature range for growth and development is 18--25°C; the suitable soil temperature is 12--35°C, and the suitable soil temperature is 15--25°C. Therefore, according to climate changes, adjust the time for uncovering and covering the film, and especially carry out variable temperature management according to its temperature requirements, which is more conducive to accumulating nutrients and reducing consumption.

3. Carry out artificial pollination. From 8--10 a.m. every day is the peak period for male flower opening. Pick male flowers, remove their corollas, and gently place the anthers on the stigma of female flowers. One male flower can pollinate 3 female flowers, and pollination is more effective when air humidity is relatively high. Pollination should be uniform and thorough. To ensure fruit setting, hormone treatment can also be used: 20--30 mg/L 2,4-D can be applied on the same day of flowering in the morning with a brush dipped in the liquid to the pedicel or ovary, but be careful not to let the liquid spill onto the stems and leaves to prevent phytotoxicity; 40--50 mg/L tomato hormone can also be sprayed on the stigma of female flowers.