A Solution for Holey T-Shirts!

25th of August, 2015

HOLEY T-SHIRTS

 

By PHIL SAYER

 

 

THE SCIENTIFIC ANSWER

 

The texts and CSIRO/University publications on clothes moths state they have a preference for textile products derived from animal fibres (containing keratin) including woollens, fur, mohair, feathers and felts.

 

Items that may be damaged include clothing, blankets, carpets and rugs, upholstery and piano felts.

The most common question from pest managers about holes in clothing is T-shirts made of rayon/viscose.

The holes are distinctive up to 4mm diameter with ragged edges and are almost always seen in the centre front.

An extensive search of literature and the web brought some light to possible reasons but also added more questions.

The first revelation was the answer to the question - how can insects eat synthetic fibres such as rayon/viscose? But are they synthetic?

 

RAYON /VISCOSE

 

Rayon is a manufactured regenerated cellulose fibre. Six processes have been developed to convert purified wood pulp cellulose into a soluble compound which is spun into soft filaments that are then converted into almost pure cellulose.

Most rayon is made by the viscose process. So viscose rayon (or just'viscose') is extracted and regenerated cellulose. Structurally, it is very similar to cotton.

Rayon is a versatile fibre, it can be made to imitate the feel and texture of silk, wool, cotton and linen. Rayon fabrics are soft, smooth, cool, comfortable and highly absorbent, but they do not insulate body heat, making them ideal for use in hot and humid climates. Aesthetically it has great lustre and drapes well.

However the durability of viscose rayon is low, especially when wet.

 

SO... Rayon is produced from a natural product refined into a semi-synthetic or artificial cellulose fibre. Can clothes moths damage cellulose-based rayon (viscose)?

 

CLOTHES MOTHS

 

There are two main species of clothes moth in Australasia, the common (webbing) clothes moth (Tineola bisselliella) and the case-making clothes moth (Tineatranslucensand pellionella).

 

Common clothes moth - the larva constructs a network of tunnels and cocoons from the threads and moves and feeds within these tubes. It rarely moves far from where the egg is laid. The pupa develops nearby and the moth tends to stay in the general area to mate and lay eggs, often on the same material it fed on as a larva.

 

Case-making clothes moth - the small sturdy cases the larva build and live in provide evidence of their presence. The larva half emerge from the case to feed and move around. When they are about to pupate, they often migrate upwards and the empty pupal cases are seen near the cornice.

 

Unlike other moths, clothes moths thrive in dark, humid environments such as wardrobes and closets. It is the larvae of these moths that cause the damage, feeding on the keratin natural products of animal origin such as wool, fur etc.

 

PHYSICAL DAMAGE TO RAYON (VISCOSE) CLOTHING

 

The weakness of viscose used for clothing is the lack of strength of the fibre, especially when it is wet.

Labels often recommend dry cleaning rather than washing.

It is possible that viscose fabrics could be damaged in the wash, but that would not explain the location of the holes always being at the front at waist level.

The next obvious reason is that the T-shirt has been jagged and rubbed up against something such as a kitchen bench. There is a report on the web of a lady taping various surfaces she rubbed up against and finally stopping new garments being 'holed.'

We asked many of the owners of the T-shirts similar questions expanding it out to seat belts, washing baskets, belly-button piercings and more.

After some thought they all came back: "NO!" One even mentioned a new T-shirt that she had not worn being 'holed.'

 

THE WEB

 

The web has numerous sites that mention holes in the front of T-shirts - with rubbing/catching the T-shirt between pant button/belt and a bench edge being the most common explanation.

Seat belts, belt buckles, catching the T-shirt on a zip or button when dressing, cats, bacteria, cockroaches, battery acid, fat splatter while cooking, the washing machine/dryer etc were also considered possibilities in the web responses.

It was also suggested that holes around the armpits were may be caused by anti-perspirants/deodorants and perspiration weakening the fibres in the clothing. Cotton garments were included among those that may be damaged.

The holes were generally noticed after the garment was washed and the holes were grouped in a small area.

One of the more interesting suggestions was the use of enzymatic detergents in the wash. The action of the detergent may result in the weak viscose fibres being removed with any stains at that spot.

Modern detergents contain cellulase (an enzyme that breaks down cellulose) - and viscose materials are based on cellulose. If the detergent is removing a stain it may also remove the weakened viscose fibres.

"Enzymes provide the superior cleaning performance needed to attack stains. Generally, the earliest enzymes to be added to laundry detergents were proteases," thehousekeepingchannel. com reported.

"However, in today's dynamic marketplace, the most successful detergent brands sometimes combine proteases with amylases, lipases and cellulases to deliver outstanding cleaning performance.”

"Each of these enzymes is able to attack a specific type of stain or soil. Accordingly, the inclusion of multiple enzymes in a detergent allows the product to tackle a much broader profile of soil types.”

"What's more, multiple enzymes can work in concert to remove tough stains or soils made up of a variety of substances.”

"For example, a food stain might typically contain protein, lipid (fat) and starch, necessitating the combined actions of protease, lipase and amylase for its complete elimination."

 

PERSONAL EXPERIENCE

 

A week before Easter this year, long after the original question was posed, we started to see the occasional small moth flutter near the TV at night.

My wife then showed me her viscose T-shirt, which featured holes at the front and down one seam (also typical of moth damage).

My wife has similar style T-shirts but it is her only viscose T-shirt and the only one with damage.

I checked a 30-year-old woollen wall hanging - holes and webbing...a woollen rug appeared to have more 'fluff' than normal...two more T-shirts - both cotton, one with a few small holes at the front, low but off centre and the other with six big holes under the armpit were found, this time they were mine!

Was it coincidence that the only time I have seen a few moths around and found activity on the wall hanging that there was also holes in clothing? Most people would not have noticed the occasional moth - that turned out to be many.

 

CONCLUSION

 

There may be a variety of reasons for holes in T-shirts.

The 'rubbing' and enzyme action of detergents are plausible explanations for viscose materials but are less likely for cotton garments.

Viscose is based on cellulose with a similar structure to cotton - and, according to web comments, cotton is also regularly affected. The cause of the holes being found consistently in the 'belly-button' region can be argued positively for rubbing, detergent action AND clothes moth - assuming clothes moth damage cellulose as well as keratin.

I believe the common clothes moth is capable of damaging cellulose based (cotton and viscose) garments and attacks areas of weakness.

Any feeding results in the holes becoming more discoverable after washing because the holes are enlarged by the action of washing and they are more likely to be seen while ironing.

 

ACTIONS

 

If you are asked by a customer about holes in T-shirts, ask the customer to take careful note of what they do.

 

Ask them to check viscose and cotton items before, and after, washing.

 

Ask the customer to check for any activity of small moths - even one or two a night could mean the presence of many more.

 

The case-making clothes moth is easily detected -the spent cases area give-away.

 

Once the cause of the holes is determined action to stop the problem can be started. This should include separation of susceptible clothing from garments based on synthetics.

 

Check for any other susceptible materials in the house - wall hangings, carpet, rugs, piano felts etc. The results of the inspection will determine the actions required.