What to Do When Pumpkin Fruits Abort? Detailed Prevention and Control Methods

Pumpkin is a plant of the genus Cucurbita in the Cucurbitaceae family. The term “pumpkin” can specifically refer to Cucurbita moschata (Chinese pumpkin) within the genus Cucurbita, or broadly refer to other cultivated species in the genus Cucurbita, including Cucurbita maxima (also known as winter squash or Indian pumpkin) and Cucurbita pepo (also known as zucchini or American pumpkin). The former, due to different regional names, is also called wheat gourd, foreign gourd, Japanese gourd, and golden winter gourd; in Minnan dialect, Hakka dialect, Dapeng dialect, and Jinhua dialect it is called golden gourd; in Changde, Hunan and other places it is also called “northern gourd.” It originated in North America.

Morphological Characteristics of Pumpkin

Pumpkin is an annual trailing herbaceous plant. The fruit is mostly oval, but also elongated or round. The stem grows several meters long, roots at the nodes, is thick and sturdy, with ridges and grooves, covered with short stiff hairs; tendrils branch into 3 to 4 forks. Leaves are simple and alternate; the blade is heart-shaped or broadly ovate, with 5 shallow lobes and 5 angles, slightly soft, about 15 to 30 cm long, densely covered with down on both sides, with irregular serrations along the margin, and often with white patches along the margin and on the leaf surface.

Triangular, densely covered on the upper surface with yellowish-white bristles and down, often with white patches; leaf veins are raised, the midvein of each lobe often extends to the tip forming a small point, the underside is lighter in color with more obvious hairs, the margin has small dense fine teeth, and the tip is slightly blunt. Tendrils are somewhat stout, covered with short bristles and down like the petiole, branching 3-5 times.

The fruit stalk is stout, with ridges and grooves, 5-7 cm long; the fruit base expands into a trumpet shape. The pepo varies in shape depending on the variety, often with several longitudinal grooves on the outside or none. Seeds are numerous, long ovate or oblong, grayish-white, with thin margins, 10-15 mm long and 7-10 mm wide. Resembling orange segments, ranging from orange-yellow to orange-red. The fruit stalk has ridges and grooves, and the fruit base expands into a trumpet shape. Seeds are ovate or elliptical, 1.5 to 2 cm long, grayish-white or yellowish-white, with thin margins. Flowering period is May to July, fruiting period is July to September.

Unisexual flowers, monoecious with male and female flowers at different positions. Male flowers have a short receptacle. Calyx lobes are linear, expanding into a leaf-like shape at the tip. The corolla is bell-shaped, yellow, with 5 middle lobes, the lobes spreading outward, with wrinkles. There are 3 stamens. Anthers are coherent, and the anther cells are regularly S-shaped and curved. Female flowers have prominent calyx lobes, leaf-like; the ovary is round or elliptical, 1-locular, with parietal placentation; the style is short, with 3 stigmas, each 2-lobed. The pepo is oblate, flask-shaped, cylindrical, etc., with longitudinal grooves and ridges on the surface, smooth or with wart-like protrusions.

What to Do When Pumpkin Fruits Abort?

Causes of pumpkin fruit abortion:

The phenomenon in which a pumpkin dies after growing to about the size of a fist is called fruit abortion. The main causes of fruit abortion in high-mountain pumpkins currently include: (1) Recently excessive temperatures are not conducive to fruit setting and fruit enlargement in pumpkins, causing fruit abortion. (2) Excessive fertilizer and water, especially after pumpkin harvest, combined with inadequate pruning, often cause pumpkin vines to grow too vigorously and plants to become leggy, easily causing fruit abortion. (3) Damage to plants by diseases and pests can also cause pumpkin fruit abortion.

Preventive measures for pumpkin fruit abortion:

First, do a good job of combating high temperatures and drought.

Second, based on the growth condition of the pumpkins, adopt corresponding cultivation and management measures. For plants growing too vigorously and becoming leggy, appropriately control fertilizer and water, strengthen pollination and pruning management measures, remove excess lateral vines, promote fruit setting on female flowers of the main vine, and control leggy growth; for weaker plants, strengthen fertilizer and water management to promote fruit enlargement. For plants damaged by diseases and pests, apply the appropriate treatment: for aphids, spray with insecticides such as imidacloprid, Kangfuduo, and shensu; at the same time, prevent and control the viral diseases transmitted by aphids; for powdery mildew, use fungicides such as Fuxing, triadimefon, and Shigao; for wilt disease, promptly pull out diseased plants and disinfect with lime, then drench all plants with fungicides such as Guakuning for root prevention.