Why Did My Lemon Tree Lose Its Leaves in Summer?

Lemon trees should have leaves until autumn.

Lemon trees that lose their leaves in the summer will be unable to continue photosynthesizing, which can destroy a fruit crop. Leaves contain a series of tubes that are used to transport nutrients throughout the tree, so a loss of leaves in the summer leads to a weakened and disease-prone lemon tree.

Causes

There are a number of factors that can cause a lemon tree to lose its leaves early. Citrus rust mite, a type of mite that feeds on citrus-fruit-producing trees including lemons, has the potential to kill off all the leaves on a lemon tree if the infestation is severe. A lack of water or the application of excessive amounts of fertilizer can also contribute to early leaf loss on lemon trees.

Pesticides

The application of pesticides to control insects such as the cedar rust mite is important for maintaining the health of a lemon tree and avoiding summer leaf loss. Apply pesticides to the lemon tree throughout its growing season; there are a variety of pesticides available to help control the population of harmful insects at different growth stages. Biological controls can also be effective pesticides; for example, releasing insects that eat the cedar rust mite helps reduce the population naturally.

Cultural Control

A lack of water and excessive amounts of water can be equally damaging to the health of a lemon tree. Make sure the soil around the base of the tree drains water quickly to prevent standing water, which can suffocate the lemon tree. Water the tree at least once a week to prevent dehydration. Pruning the tree annually helps control overcrowding of the branches, reducing the likelihood of summertime leaf loss.

Fertilizer

Proper application of fertilizer is key to the health of a lemon tree. Fertilize the lemon tree in the early spring when it emerges from its dormant state and begins growing. Avoid placing fertilizer directly on the base of the tree, because this can lead to fungal growth. Apply only the necessary amount of fertilizer according to the manufacturer's directions; adding too much dehydrates the lemon tree and can cause growth problems throughout the season, including summer leaf loss.

References

• University of Florida IFAS Extension; Citrus Problems In The Home Landscape; Mongi Zekri and Robert E. Rouse; July 2010
• University of Arizona; Citrus Leaf Drop in the Low Desert; June 1998
• Texas A&M University; Diagnosis of common citrus problems

Resources

• Texas A&M University; Home Fruit Production - Citrus; Julian W. Sauls