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Ambrosia Beetle

Ambrosia beetle traps were set at three farm operations in Chilton County February 27, 2020 and monitored weekly. The first ambrosia beetles were discovered on March 19 at all locations (Table 1).

Table 1. Ambrosia Beetles trapped at three locations in Chilton County, AL. from March 1 – 19, 2020.

1Letter H indicates ambrosia beetles found that typically infest healthy trees
2Letter S indicates that presence of ambrosia beetles that are known to infest stressed as well as healthy trees.
OperationSettingLocationAmbrosia Beetles Found
Farm 1Orchard/FruitCentral Chilton Co.H1, S2
Farm 2Nursery/Orchard FruitCentral Chilton Co.H, S
Farm 3OrchardSouth Chilton Co.S

 

Trapped ambrosia beetles are an indication that preventative sprays should be applied to trunks of vulnerable orchard or landscape trees. Vulnerable trees are those that are stressed, in decline, or young trees. Some species of ambrosia beetle (Figures 1 and 2) may infest trees, which are apparently healthy. This type of ambrosia beetle was discovered at both farm locations in central Chilton County but was not found in south Chilton County.

Trees that are infested with ambrosia beetle will sometimes have matchsticks jutting out from the trunk (Figure 3). These matchsticks are sawdust particles mixed with beetle feces stuck together as they are being extruded from the hole created by the female ambrosia beetle as she is excavating tunnels to rear her young. Once matchsticks are observed, spray treatments will not rid the tree of ambrosia beetles.

Treatment

Treatments to control of ambrosia beetle are preventative. As mentioned above chemical treatments cannot control ambrosia beetles once established in the tree. To prevent ambrosia beetle infestation, a monitoring program should be used. Monitoring consists of traps, which use an ethanol lure (Figure 4). The ethanol in the lure mimics the scent of declining or stressed trees. Traps should be monitored at least once per week. Once ambrosia beetles are discovered in traps, a spray program can begin. Spraying of pyrethrins as a preventative measure has been effective.

Contact your regional agent or specialist with questions you might have concerning proper identification or chemical control of ambrosia beetles. Be sure to read the label before applying any chemical control methods.

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