Destructive Insect Invader: Pear Sawfly, Also Known As Pearslug
In the blooming gardens of Iowa and beyond, a common pest known as the pear sawfly can cause significant damage to a variety of plants, including pear, cherry, crabapple, apple, plum, hawthorn, cotoneaster, and mountain ash. This article provides an overview of effective methods for controlling pear sawflies in their larval stage, focusing on both mechanical and chemical approaches.
First and foremost, early detection and removal are key to managing pear sawfly infestations. Visual inspection of infested leaves, especially on the underside where larvae hide, followed by manual removal, is a practical method for small-scale or home gardens. Pruning affected leaves or branches can also help reduce larval populations. Removed larvae can be dispatched by crushing, drowning in a vessel of water, diluted hydrogen peroxide, or insecticidal soap.
For larger infestations, chemical controls may be necessary. Recommended insecticides include Spinosad or Neem oil, which are effective against young sawfly larvae, and traditional insecticides such as maldison, dimethoate, carbaryl, and imidacloprid. It's essential to target young larvae, as they are easier to control before causing significant damage. Applying sprays directly to the larvae for maximum effectiveness and timing applications to correspond with hatching or early larval feeding stages can increase insecticide impact and reduce resistance buildup.
When using insecticides, it's crucial to minimize harm to beneficial insects. Avoid broad-spectrum insecticides where possible and follow label instructions carefully. For large-scale or commercial settings, integrated pest management (IPM) practices may combine biological controls (natural predators and parasites) with chemical treatments to reduce sawfly populations sustainably.
Pear sawfly larvae feed on leaves for about 4 weeks before dropping to the ground, burrowing into the soil, and pupating to emerge as adults that produce a second generation in late July or August. Management of pear sawflies should commence while the larvae are still small. It's important to note that the pear sawfly overwinters in a cocoon 2 to 3 inches below the soil surface.
Always ensure the specific host is listed on the insecticide label before using a product, and avoid applying insecticides toxic to pollinators on plants that are in bloom. The adult form of the sawfly is a harmless wasp, resembling shiny, black flies, about 1/5 inch long, with darkened wings.
In conclusion, early detection and removal, combined with targeted use of insecticides like Spinosad or Neem oil on young larvae, constitute the most effective control strategies for pear sawflies. Proper timing and application method are crucial to minimize environmental impact and enhance efficacy.
- A visual inspection of infested leaves, particularly on the underside where larvae hide, is a practical method for small-scale or home gardens to manage pear sawfly infestations.
- For larger infestations, chemical controls such as insecticides like Spinosad or Neem oil, maldison, dimethoate, carbaryl, and imidacloprid may be necessary, targeting young larvae for effective control.
- Integrated pest management (IPM) practices, which combine biological controls and chemical treatments, can be beneficial in large-scale or commercial settings to reduce pear sawfly populations sustainably.
- Pear sawfly larvae burrow into the soil and pupate to emerge as adults that produce a second generation, so management should commence while the larvae are still small.
- It's important to ensure the specific host is listed on the insecticide label before using a product and to avoid applying insecticides toxic to pollinators on plants that are in bloom.
