Fruit Drop

Natural fruit drop is a result of unfertilized or poorly fertilized seeds, cold injury, competition between fruits, or shading

• Poor pollination may be a result of cold, rainy weather during bloom in self-fertile fruits such as peaches or poor insect pollinator activity during flowering in insect pollinated fruits such as apples

• In stone fruit, some fruit that is not fertilized will remain on the plant for 25-50 days after bloom and then will drop before pit hardening starts
• Another wave of natural fruit drop occurs in late May or early June
• This fruit drop is due to competition between fruit for sugars stored and produced by the tree
• A tree can only carry a certain load of fruit and will naturally drop smaller and weaker fruit during this period
• However, thinning should have been accomplished before this competitive fruit drop occurs
• Having fruit remain on the plant until natural competitive drop will use up food reserves in the plant and reduce the size potential of remaining fruit
• Fewer cells will have been produced by the fruit remaining on the plant and therefore fruit size will not be recovered
• Another cause of fruit drop is cloudy weather during the period 5 to 7 weeks after bloom
• A continuous 4 day period of cloudy days during this period will also cause fruit to drop
• In addition, defoliation due to disease such as peach leaf curl, chemical injury such as copper fungicide damage, or severe storms can cause fruit drop during this critical period