Latin: Ephestia Kuehniella
This flour moth has caused a great deal of damage since it was found in a batch of wheat from America in 1877. The flour moth originates from somewhere between Asia and the Middle East, and it has since invaded mills, grain warehouses, and bakeries throughout Europe and North America.
Flour moths is rarely a problem in private homes, but it can nonetheless be a problem in certain situations. Most often, the moths and moth larvae found in private homes are instead a two-colored seed moth. Flour moth is more often a problem in the industry.
Appearance
The flour moth has an elongated shape with narrow wings. Its body is about 10-12mm long, and a wingspan of 20-22 mm. Compared to other species of moths, flour moth may look a little thin when resting. Their wings are narrow, and they lay them flat over their backs when they are not flying. The flour moth can be recognized by its colors on the wings. The forewings have a lead gray color with a pattern. The pattern is zigzag with transverse lines and dots. The hind wings are a lighter shade of gray with fringes on the trailing edge.
A larva from a flour moth is typically between 15 and 19 mm, so relatively short compared to the adult moth. An exciting thing about the larvae is that they can have different colors. They are either white, pink, or light green as larvae. They all get the same color when they are fully grown larvae.
Biology and behavior
Adult moths are particularly active at dawn and around dusk. Here they fly around looking for a mate or, if they have already found a mate, to lay eggs. Flour moth can mate as soon as they hatch. From mating, it only takes a few hours for the female to lay her eggs.
A female can in average lay 200 eggs, which then take 1-2 weeks to hatch. The eggs are often laid in flour, from which the moth got its name.
The hatched larvae immediately begin to eat the flour. They can also eat grains, seeds, brants, and other dry goods, depending on where their eggs have been laid. Then the larvae begin to spin silk threads. The flour moth larvae have a sticky web. It is this web that creates difficulties for the industry.
The larva’s sticky silk attracts flour, dust, and the larva’s own excrement. This can give small pockets of extremely unsightly odor and contaminated flour.
Both adult flour moth and their larvae will try to create a dark habitat or search for dark corners of wherever they live. Therefore, the moth larva is rarely seen, as it simply digs deep into the stock of flour until it is fully grown. As a full-grown larva, it begins to pupate. The puffing time of the flour moth lasts 17-20 days, after which the adult flour moth immediately looks for a mate.
Damage
It is especially the larva that damages stocks of flour and similar goods. The moth is of course also a problem, as it is the adult flour moth that lays the eggs in the flour.
Flour can be difficult to control, as most insecticides are toxic to humans. Flour moths are also difficult to detect before the accidents are massive.
They are harmful to the industry, as they both eat and spin. They eat flour and similar foods (grains, seeds, pasta, almonds, dried fruit and more), and spin their silk threads in the same foods. This silk thread creates difficulties just as much as eating the inventory. The silk thread attracts excrement, food, dirt, and everything else, which destroys the stock.
Prevention and control
Nowadays, it can be difficult to avoid flour moth in companies that process food. However, the biggest risks is returned goods and packaging, which is why these should be stored separately from the production. Ideally, returned goods should be stored in a completely different room than the production, preferably further away.
Cleanliness is also a good way to prevent. Sweeping and vacuuming flour and dust will minimize the risk of eggs being laid in it. Pipes, funnels, and screens should be cleaned regularly, and so should machinery and the premises themselves. Flour sacks or the like should not be allowed to lie directly on the floor or stand up against walls. Instead, these should be placed on benches so that sweeping can be done under them. In addition, keep storage rooms well ventilated so that the goods are dry, and low temperature.
It is extremely difficult to control flour moth. Many insecticides are toxic to humans, which is why they cannot be used in food. Others simply create odor nuisances, which can nonetheless ruin an entire inventory. In addition, many of the more human-friendly agents are not nearly as potent, so typically need to be sprayed frequently. One’s best bet is to keep an eye on prevention.
Specifically, in flour silos
Silos for flour at bakeries have gradually become very normal. However, these can lead to flour moths. It is therefore important that flour silos at bakeries are completely emptied at least every three months. After the silo has been emptied, it must be thoroughly cleaned. Here, it can therefore also be smart to make sure that you do not fill more in the silo than can be used in three months.
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