Do Blueberries Need Pesticides? A Detailed Guide to the Best Pruning Time
The blueberry is a blue berry, currently distributed in many countries around the world, and is a fruit with an excellent taste. In recent years, more and more people in China have also begun to grow blueberries, but when growing them, many people are not very clear about its pruning time and pruning techniques, nor do they know whether it actually needs pesticides to protect the fruit.
Do Blueberries Need Pesticides?
Judging from the current growing situation, blueberries have a relatively strong ability to resist pests and diseases, and under normal circumstances the damage is not serious. Apart from preventing birds during the fruit-ripening period (by putting up protective netting), there is basically no need for chemical control. However, it cannot be ruled out that spraying may be needed, because blueberries are not 100 percent immune to the attack of pests and diseases; once they are found, pesticides need to be sprayed to control them. When spraying pesticides, the pesticide is chosen according to the different disease conditions, and then treatment is carried out.
Which Month Is Best for Pruning Blueberries?
The best season for planting blueberry crops is autumn, around October each year. After planting, blueberry crops should be properly shaded, otherwise the crops will become dehydrated, and growers should shade the blueberry crops in good time.
Pruning Techniques for Blueberries
I. Pruning of highbush blueberries
1. Pruning in the young tree stage. At this stage, the main task is to remove flower buds, with the aim of expanding the canopy, increasing the number of branches, and promoting root development. In the second and third spring after planting, remove the weak and small branches. In the third and fourth years, the main focus is still on expanding the canopy, but a moderate amount of fruiting is allowed. Generally, in the third year the yield per plant should be kept below 1 kg, with fruiting mainly on strong branches.
2. Pruning of mature trees. At this time, pruning is mainly to control tree height and improve light conditions, with thinning of branches as the main approach, removing overly dense branches, thin and weak branches, pest- and disease-damaged branches, and root suckers. For varieties with a more spreading growth habit, when thinning branches, remove the weak and keep the strong; for upright varieties, remove the central leader, open up the top, and keep medium-sized branches. The best tree age for fruiting on large branches is 5 to 6 years old; beyond that, they should be promptly cut back and renewed. On weak and small branches, remove the flower buds to make them grow stronger. Mature trees have a large number of flowers, so part of the flower buds should be cut off, generally leaving 2 to 3 flower buds per strong branch.
3. Renewal of old trees. About 25 years after planting, the above-ground part of the tree has aged and the whole tree needs to be renewed, that is, all the above-ground parts are sawn off close to the ground, and new branches sprout again from the base.
II. Pruning of lowbush blueberries
1. Fire pruning. That is, during the dormant period, burn off all the above-ground parts, so that new branches sprout again, form flower buds that same year, and bloom and bear fruit the following year. After that, fire pruning is carried out once every 2 years, always maintaining fruiting on strong branches.
2. Mowing pruning. Before budding in early spring, cut the above-ground part flat from the base of the plant, sawing it all off. The sawn-off branches are left in the orchard, where they can serve to cover the soil and raise organic matter.
Common Diseases of Blueberries and Their Control
1. Leaf spot: Control measures: promptly pick off diseased leaves and old leaves. In the early stage of the disease, use 70% chlorothalonil wettable powder at 500 to 700 times dilution, and spray again after ten days. Or use 70% mancozeb wettable powder, 200 grams per mu mixed with 75 kg of water for spraying.
2. Powdery mildew: Control measures: on the central diseased plants and around them, focus on spraying 0.3 degrees Baume lime sulfur mixture. After harvest, cut all the leaves in the whole orchard and spray 70% thiophanate-methyl at 1000 times dilution, or 50% thiram at 800 times dilution, or 30% triflumizole at 5000 times dilution, etc.
3. Gray mold: Control measures: carry out from the bud stage to the flowering stage, spraying 25% carbendazim wettable powder at 300 times dilution, 50% captan wettable powder at 800 times dilution, 50% iprodione at 500 to 700 times dilution, etc.
4. Root rot: Control measures: before transplanting the strawberry, use 40% asparagus green powder at 600 times dilution, pour it on the bed surface, then cover with soil, level and transplant, so as to effectively kill the pathogens in the soil, lower the base number of inoculum in the field, and reduce the chance of infection.
Overall, once pests and diseases are found on blueberries, pesticides are also needed. Pruning is very important when growing blueberries, and the pruning time is generally in the autumn of each year. Its pruning methods also differ depending on the age of the tree, so everyone must pay close attention.