Leaffold Caterpillar on Weeping Redbud - Ask Extension
How should I manage an infestation of leaffold caterpillar on my weeping redbud tree? I am loacated in West Bloomfield Township in Oakland County.
Knowledgebase
Leaffold Caterpillar on Weeping Redbud #805436
Asked August 09, 2022, 1:05 PM EDT
How should I manage an infestation of leaffold caterpillar on my weeping redbud tree? I am loacated in West Bloomfield Township in Oakland County.
Oakland County Michigan
Expert Response
The purpose of the leaf-folding is to enable the caterpillar to feed on the upper surface of the leaf and be protected. Feeding can lead to browning, dying and death of the leaves.The redbud leaf-folder overwinters as a dark brown pupa attached with a loose web to a fallen leaf. If removed from the leaf, they may still thrive in leaf litter or on the soil surface. Adult leaf-folder moths are about an inch long with a wingspan of about an inch. The moth has dark brown wings with 10 small, white spots, a white head and a collar.
Moths of the leaf-folder emerge in the late spring, laying small, white, oval eggs near leaf veins during May. The first generation of eggs will continue hatching through June, followed by second- and third-generation eggs laid in late summer to fall. These eggs may be laid in a fine web on the leaf. The damaging stage of the leaf-folder is the larvae or caterpillar stage. The young larvae are white but mature to dark caterpillars with white bands along the back.
There are several methods for controlling leaf-folding larvae. First and foremost, only spray if damage is severe and the tree is young. Mature trees can handle defoliation due to some insect feeding. However, young trees may be severely stunted in extreme cases. Make sure you follow up with proper water and fertilizer practices.
If only a couple leaves are damaged, treatment is not warranted. Simply pluck off and dispose of infested leaves. Sometimes during rainy weather, a fungal disease can attack and kill leaf-folder larvae. The organic insecticide Bacillus thuringiensis (Bt) is effective against the larval stages of many types of leaf-feeding larvae, including leaf-folders. Bt is a bacterial-based insecticide that kills moth and butterfly caterpillars but does not harm other beneficial insects, birds, humans or other organisms. With Bt, leaf-folders will cease feeding within hours after ingesting a sprayed leaf and will die several days later. Thorough spray coverage of the tree is required for control, and Bt is not waterproof. Bt is most effective on leaf-folder larvae when small and sufficient control may require more than one application. Raking and disposing of dropped leaves in the fall may also be a means of control.
The link below discusses an optional control method:
https://content.ces.ncsu.edu/redbud-leaffolder
However, Redbud leaffolder caterpillars are difficult to manage with spray applications of insecticides once the leaves are fastened together because the caterpillars are protected from exposure inside the folded leaves. However, folded leaves can be physically removed and placed into a container of soapy water that will kill redbud leaffolder caterpillars.
And here is some additional information which again suggests that spraying is difficult and often not warranted or effective.
https://bygl.osu.edu/node/884
Moths of the leaf-folder emerge in the late spring, laying small, white, oval eggs near leaf veins during May. The first generation of eggs will continue hatching through June, followed by second- and third-generation eggs laid in late summer to fall. These eggs may be laid in a fine web on the leaf. The damaging stage of the leaf-folder is the larvae or caterpillar stage. The young larvae are white but mature to dark caterpillars with white bands along the back.
There are several methods for controlling leaf-folding larvae. First and foremost, only spray if damage is severe and the tree is young. Mature trees can handle defoliation due to some insect feeding. However, young trees may be severely stunted in extreme cases. Make sure you follow up with proper water and fertilizer practices.
If only a couple leaves are damaged, treatment is not warranted. Simply pluck off and dispose of infested leaves. Sometimes during rainy weather, a fungal disease can attack and kill leaf-folder larvae. The organic insecticide Bacillus thuringiensis (Bt) is effective against the larval stages of many types of leaf-feeding larvae, including leaf-folders. Bt is a bacterial-based insecticide that kills moth and butterfly caterpillars but does not harm other beneficial insects, birds, humans or other organisms. With Bt, leaf-folders will cease feeding within hours after ingesting a sprayed leaf and will die several days later. Thorough spray coverage of the tree is required for control, and Bt is not waterproof. Bt is most effective on leaf-folder larvae when small and sufficient control may require more than one application. Raking and disposing of dropped leaves in the fall may also be a means of control.
The link below discusses an optional control method:
https://content.ces.ncsu.edu/redbud-leaffolder
However, Redbud leaffolder caterpillars are difficult to manage with spray applications of insecticides once the leaves are fastened together because the caterpillars are protected from exposure inside the folded leaves. However, folded leaves can be physically removed and placed into a container of soapy water that will kill redbud leaffolder caterpillars.
And here is some additional information which again suggests that spraying is difficult and often not warranted or effective.
https://bygl.osu.edu/node/884
