Potentialities of Natural Dyestuffs as Antifeedants against Varied Carpet Beetle, Anthrenus verbasci

We studied damage to wool fabrics dyed with different natural and chemical dyestuffs by the larvae of varied carpet beetle, Anthrenus verbasci, as part of a study on the functions of natural dyestuffs. Eight of ten natural dyestuffs showed an antifeeding effect against A. verbasci. Strength of the antifeeding effect of natural dyestuffs in a feeding preference test was in the order lac dye, gallnut, catechu, red cabbage, Cricula cocoon extract > cochineal, indigo, Amur cork tree extract > chemical dye. Lithospermi radix and turmeric were less effective against A. verbasci. The damage to dyed fabrics by the insect was not related to the extent of color depth or shade of the dyed fabric. Water-soluble substances having absorption peaks at around 280 nm, commonly were present in the natural dyestuffs except for turmeric. The polyphenols, tannic acid and catechin having absorption peaks at around 280 nm, seemed to be not related with the antifeeding effect. An alkali degummed Cricula cocoon sample that had almost all of the cocoon filament sericin removed showed almost the same level of damage by insect feeding as that of natural Cricula cocoons. Discipline: Insect pest Additional key words: fabric insect pest, extracts of natural pigment, feeding test, feeding preference test, absorption spectra the feeding damages to wool fabrics, which had been Introduction Natural dyestuffs produced by plants and insects have been used not only for dyeing silk but also as coloring agents in food and cosmetic industries. The interest in these natural dyestuffs is increasing because of recently discovered useful functions such as antioxidant effects and antibacterial effects, in addition to the positive feelings people have about their safety. They have also gained popularity for the sober and elegant shades that they give to fabrics. It is traditionally believed that many of these natural dyestuffs are effective against insect attack and have some medicinal value. There is an old saying that if a garment is wrapped in a yellow wrapping cloth dyed with turmeric or Amur cork tree extract, it would be protected from insect attack. Feeding inhibition of fabric insect pests, black carpet beetle, Attagenus unicolor japonicus, and varied carpet beetle, Anthrenus verbasci, by buds of clove, Syzygium aromaticum, and calyxes of Cinnamomum obtussifolium have been examined. Nakajima (1999) studied widely dyed in a dyeing system containing natural dyestuffs in the presence of mordanting agents, by larvae of casemaking clothes moth, Tinea translucens, and webbing clothes moth, Tineola bisselliella, and concluded that the sample dyed with plant dyestuff bayberry, Myrica rubra, demonstrated the highest antifeeding effect among the dyed wool samples examined. Although there are several papers, discussing the antifeeding effect of repellent substances, feeding habit of A. verbasci larvae and so on, very few research papers on the antifeeding effect of natural dyestuffs have been reported. Additionally, very few scientific studies have been carried out focusing on the analysis of the antifeeding factors in natural dyestuffs. We, therefore, studied the antifeeding effect of representative natural dyestuffs derived from plants and insects on the beetle. Further, we used the pigment extracted from cocoons of Cricula trifenestrata as one of dyestuff from insects. The reasons for using the pigment extract from Cricula cocoons are as follows: (1) it is a kind of natural dyestuff of insect origin, (2) as its common name “golden cocoon” H. Kato & T. Hata contributed equally to this work. *Corresponding author: fax +81–29–838–6160; e-mail [email protected] Received 27 August 2003; accepted 23 June 2004.