Anomala orientalis (Waterhouse, 1875)
Kingdom: Animalia (Animals)
Phylum: Arthropoda (Arthropods)
Class: Insecta (Insects)
Order: Coleoptera (Beetles) Linnaeus, 1758
Family: Scarabaeidae (Scarab Beetles) Latrielle, 1802
Genus: Anomala Samouee, 1819
Species: Anomala orientalis (Oriental Beetle)
Other Names: Phyllopertha orientalis, Blitopertha orientalis, Exomala orientalis
The Oriental Beetle is not native to North America. It was discovered as a serious pest to sugar cane in Hawaii in 1908 -thought to have arrived in the soil of imported plants. Subsequently, the invader made way for New Haven, CT in balled nursery plants in 1920. It was known to exist within 90 miles of New York City in 1933, but has now expanded its range to other areas (clearly Massachusetts as is documented in the pictures shown here).
This pest damages both lawns (turfgrass) and crops (sugar cane, blueberry, cranberry, raspberry).
If you have seen them in your area, please comment below.
Adults emerge starting in June and can be found for two months.
Females depoit around 25 eggs underground from Early July to September approximately 12 cm deep. The larvae hatch within days and begin to feed on grass roots until they overwinter at greater depths to avoid feezing. They go through 3 larval instars
Grub damage will appear as random patches of dead grass. If many grubs are present you may also notice small holes from skunks and other animals in your lawn. This further damages your lawn.
Methods of Control
Historically lead arsenate was used on crops to control this pest, but should no longer be used due to the serious effects that these heavy metals have on health. It was believed by some that use of this pesticide would not result in the accumulation of lead and arsenic in plant tissues, but recent studies show that in contaminated soils with more than 100-200 mg/kg Pb that lead can reach levels above international health-based standards in carrots and leafy greens. Arugula will easily accumulate arsenic. This has led scientists to search for other control methods, including introduction of a nemotode Steinernema scarabaei as a biocontrol agent.
Scientists have isolated the female pheromone by watching males choose to fly towards the isolated secretions in a tube. This may provide a means of biocontrol without using harsh chemicals.
Garden canters sell GrubEx with the active ingredient Chlorantraniliprole, The downside this chemical is that non-target arthropods may also be killed. It works by disrupting the necessary calcium release in muscle cells required for muscle contraction resuting in paralysis and death of exposed insects.
Other color morphs have been observed. If you have observed these in your area, please leave a comment below to let us know about your find.
Where to Find Them
This adult pictured here was found on a King George Day Lily in a residential garden. It seemed content to just rest on the petal and was not observed feeding. The adults are not known for destructive feeding – it is the grub stage that may destroy your lawn.