What is the best time to control excessive vine growth in sweet potatoes?

During the growth period of sweet potatoes, excessive vine growth can occur, and if not addressed in time, it can lead to reduced yield. So what is the best time to control excessive vine growth in sweet potatoes?

1. What is the best time to control excessive vine growth in sweet potatoes?

1. First growth control: during the first tuber expansion period of sweet potatoes, when the vines are about 35-45 cm long and the vines have begun to hang down from the ridges, commonly known as “xia liangzi”, elegantly described as “the two ridges seem to hold hands yet not quite”. This is the branching and tuber-setting stage of sweet potatoes, when branches form above ground and tubers form below ground, so it is very critical.

2. Second growth control: generally about 65-70 days after planting, when the “rainy season” begins, with high temperature and high humidity. This is the season when sweet potato stems and leaves grow fastest, in the stage of simultaneous vine and tuber growth, but tubers expand relatively slowly, so strong control is needed at this time.

3. Third growth control: generally about 85-90 days after planting, when the growth of sweet potato stems and leaves reaches its peak. To prepare for the arrival of the second tuber expansion period of sweet potatoes, growth control should also be carried out in time. During the second tuber expansion period of sweet potatoes, when the vines are about 60-80 cm long and the ridges are basically closed, this is the golden period for sweet potato development, and strong control should be applied.

2. How to control excessive vine growth in sweet potatoes?

1. For sweet potatoes showing signs of excessive vine growth, when the vines reach about 35 cm, use 20-30 g of 5% uniconazole wettable powder, mix with 30 kg of water and spray once. Before the ridges close, when the vines are about 50 cm long, spray once more, and this can effectively control excessive vine growth in sweet potatoes.

2. Alternatively, when sweet potatoes grow to the mid stage and the vines are 50-70 cm long, use 100 g of 15% paclobutrazol per mu, mix with 15 kg of water and spray on the leaves, generally once every two weeks, for 2 to 3 consecutive sprays.

3. Alternatively, when sweet potato vines grow to 50-60 cm, spray 10 mL of mepiquat chloride or 20-25 mL of growth promoter per mu, which can control above-ground growth, promote root growth, and have an obvious yield-increasing effect.