Can Chrysanthemum control flour beetle infestation?

Confused flour beetles (Tribolium confusum) are one of the most serious pests in stored grain since it can easily live and feed off damaged grain products. Flour beetles are highly resistant to traditional insecticides, so farmers and scientists are constantly searching for new chemicals and methods to fend off these resilient pests. This proves to be a difficult undertaking as any novel insect control agents must be safe enough to not cause damage to stored grains and agriculture while still be potent enough to ward off the indestructible king of insects.

A joint-team from the University of Sousse and University of Pisa, led by Dr. Haouas, has recently discovered the deterrent effects of Chrysanthemum on confused flour beetles. In their study, published this year in the Journal of Pest Science, the researchers analyzed essential oils from three species of Chrysanthemum (C. coronarium, C. fuscatum, and C. grandiflorum) and for their toxicity and anti-feeding properties. Essential oils are volatile liquid compounds extracted from plants via distillation; the term is derived from the “essence” or aroma of specific plants.

C. coronarium

C. fuscatum

C. grandiflorum

The flour beetles were starved for 24 hours to induce feeding on the Chrysanthemum-laced flour. Essential oils from the leaves and flowers of each Chrysanthemum species were tested for their effects on confused flour beetle’s mortality and toxicity.

The winner of the three Chrysanthemum species proved to be C. grandiflorum. Essential oils from the leaves of this species was most effective in inhibiting the relative growth rate, efficiency of conversion of ingested food, relative consumption rate, caused an anti-feeding effect, and a high mortality (80%) of T. confusum larvae.

The runner-up was C. coronarium flowers which had essential oils that demonstrated significant lethal toxic effects to flour beetle larvae both through contact and gaseous fumigation.

C. fuscatum was also found to be particularly rich in limonene which is one of the most toxic compounds to T. confusum.

A drop a day, keeps the flour beetles away!

The insecticidal characteristics of Chrysanthemum on flour beetles should increase the use of natural plant materials in pest control as potent alternatives to synthetic pesticides. This technique offers important implications for poor farmers who cannot afford commercial pesticides to banish flour beetles through traditional methods of pest control, such as pouring a few drops of Chrysanthemum oil in stored grain.

References:

Haouaus D., Cioni P.L., Ben Halima-Kamel M., Flamini, G., Ben Hamouda M.H. 2012. Chemical composition and bioactivities of three Chrysanthemum essential oils against Tribolium confusum. J Pest Sci 85(3): 267-279.

Stamopoulos DC, Damos P, Karagianidou G. 2007. Bioactivity of five monoterpenoid vapours to Tribolium confusum (du Val) (Coleoptera: Tenebrionidae). J Stored Prod Res 43:571–577.

---