Pawpaw damage - Ask Extension
Hi. What do you think could be eating my pawpaw sapling leaves? I do not see any insects on the plants when I inspect them. I have been spraying them ...
Knowledgebase
Pawpaw damage #871372
Asked June 03, 2024, 4:23 PM EDT
Hi. What do you think could be eating my pawpaw sapling leaves? I do not see any insects on the plants when I inspect them. I have been spraying them with a neem oil solution every week or so. And spread out some slug bait just in case. Is there anything else I can do? Thank you!
Montgomery County Maryland
Expert Response
Pawpaw is the caterpillar host plant for the Zebra Swallowtail butterfly, and while this particular chewing damage does not appear to be caused by those caterpillars, we discourage insecticide use (of any type) on pawpaw since they could harm those larvae or any eggs laid by adult butterflies. Zebra Swallowtail caterpillars do not cause serious damage to the plant. There are a few photos in the linked galley page showing what the egg and caterpillar stages look like.
Other insects can feed on pawpaw foliage, but they similarly do not cause serious harm to the plant, even if damage looks prominent. No intervention is necessary.
Neem oil is a type of horticultural oil. Even though horticultural oils are low-toxicity insecticides, they still are somewhat broad-spectrum, in that they can affect any insect that the spray comes into direct contact with, beneficial or not. Given that, treatments also only work when the spray comes into direct contact with the pest; dried residues will not have any impact, so it cannot be used as a preventative spray and applied when the culprit of damage is not present and visible. Identifying the cause of damage is important before taking action, as either an insecticide may not be needed, or the type of insecticide chosen will depend on the particular pest present.
One possibility for the pictured chewing damage is beetles. There are many species active now, and some are generalists, feeding on a wide variety of plant species. Many feed at night, so you could inspect the plant after dark to see if any insects (or slugs/snails) are on either the upper or lower surface of the leaves.
Trees and shrubs can afford to lose some foliage or leaf surface area to insect feeding, weather damage, infection, and other causes of injury to the leaf. Intervention for this mild level of damage is not needed, though you can keep an eye on the plant for new or worsening symptoms aside from chewing. The most important aspect of plant care for young and new transplants is to monitor them for watering needs during their first couple of growing seasons as their root system becomes established.
Miri
Other insects can feed on pawpaw foliage, but they similarly do not cause serious harm to the plant, even if damage looks prominent. No intervention is necessary.
Neem oil is a type of horticultural oil. Even though horticultural oils are low-toxicity insecticides, they still are somewhat broad-spectrum, in that they can affect any insect that the spray comes into direct contact with, beneficial or not. Given that, treatments also only work when the spray comes into direct contact with the pest; dried residues will not have any impact, so it cannot be used as a preventative spray and applied when the culprit of damage is not present and visible. Identifying the cause of damage is important before taking action, as either an insecticide may not be needed, or the type of insecticide chosen will depend on the particular pest present.
One possibility for the pictured chewing damage is beetles. There are many species active now, and some are generalists, feeding on a wide variety of plant species. Many feed at night, so you could inspect the plant after dark to see if any insects (or slugs/snails) are on either the upper or lower surface of the leaves.
Trees and shrubs can afford to lose some foliage or leaf surface area to insect feeding, weather damage, infection, and other causes of injury to the leaf. Intervention for this mild level of damage is not needed, though you can keep an eye on the plant for new or worsening symptoms aside from chewing. The most important aspect of plant care for young and new transplants is to monitor them for watering needs during their first couple of growing seasons as their root system becomes established.
Miri
