They are food moths and don't seem to disdain any food in the pantry. Dried fruit moths attack various foods and are difficult to get rid of. Once you have it, you face a test of patience. But with appropriate measures, the plague can be combated effectively.
How can you combat and prevent dried fruit moths?
Dried fruit moths can be effectively combated with pheromone traps, chemical agents, home remedies or beneficial insects such as parasitic wasps. Hot air kills larvae and pupae, while essential oils such as lavender, clove or cedar confuse adult moths. As a preventive measure, food should be tightly closed and newly purchased goods should be checked regularly.
Fighting dried fruit moths
Anyone who has ever noticed an infestation by the dried fruit moth needs patience. If you want to get rid of the pests, you should not only take direct control measures. Prevention is just as important so that the drama does not repeat itself.
Pheromone trap
Such a trap contains sexual attractants that attract males. They stick to the adhesive surface after landing. However, this measure is not suitable for combating them because neither females nor larvae are attracted to the scents. You can use pheromone traps to check whether there are dried fruit moths in your household. The attractants are species-specific, so you need a product specifically for the dried fruit moth. The traps can be used over several weeks.
Pheromone traps are widely used in the fight against dried fruit moths
Chemical Agents
Various insecticides are available commercially that you can use to destroy the larvae. The products often contain the natural substance pyrethrum, which is obtained from various Tanacetum species. They are sprayed into the hiding places of the larvae so that they die within a short time.
There are special insect strips to combat dried fruit moths. They consist of a fleece that is protected by a grid. Over several months, the fleece releases a chemical agent into the air that is supposed to destroy the moths. However, such chemical agents are not harmless to humans either.
Beneficial insects
The use of parasitic wasps of the genus Trichogramma is effective and harmless to he alth. They are parasitic and lay their eggs in the eggs of the dried fruit moth using a long stinger. The wasp larvae eat the eggs from the inside. Adult parasitic wasps look for new clutches to lay their eggs. While the beneficial insects are doing their work, you should not use the vacuum cleaner.
Advantages:
- Beneficial insects are hardly noticed
- no danger to humans
- Parasitic wasps disappear as soon as they do not find moth eggs
Bekämpfung von Motten mit Nützlingen (Trichogramma)
Remove with home remedies
Dried fruit moths avoid certain foods such as fats and oils, sugar and s alt as well as heavily smoked foods. Many other products are not safe and should be discarded if an infestation occurs. You must then take further measures to prevent the pests from spreading any further.
Tip
Vacuum niches and clean refrigerator, shelves and surfaces with vinegar water.
Hot Air
If your furniture is sturdy and unpainted, you can heat up cracks and crevices with a hairdryer for a few minutes. The hot air kills larvae and pupae and prevents the eggs from developing further. This method is very effective because the hot air reaches even hard-to-reach places.
Cold and heat treatment
If you notice an infestation of dried fruit moths, you should also treat the intact food as a precaution. Freeze food for about a week. Eggs and larvae can no longer survive in the freezing temperatures in the freezer. They can survive temperatures down to minus ten degrees Celsius for short periods of time. You can achieve the same effect if you heat food in the oven to 60 to 80 degrees Celsius.
Fragrance Oils
It is often advisable to distribute intensely smelling plants or scented sachets in different corners of the room. Scented oils of lavender, clove or cedar are said to confuse adult moths as they search for a place to lay their eggs. However, this leads to the moths looking for other hiding places. Fragrance oils do not help against larvae, eggs and pupae.
Lavender bags confuse the moths
Prevention
Since the eggs cannot be seen with the naked eye, infected foods can rarely be identified in the supermarket. However, you can sometimes find evidence of a pest infestation.
Check purchased food
The dried fruit moth often comes into the house with animal feed. If you put together feed mixtures from open self-service counters in specialist stores, you should pay attention to possible pests. Do not buy if you find beetles, larvae or maggots in the food. Packaged food should not show any damage. Small holes in paper and foil indicate an infestation.
Tip
Buy small quantities instead of storing large supplies. When storing food, ensure cool and dry conditions.
Store food safely
A screw-top jar is often not enough to store food safely. The young larvae are able to crawl through the thread into the interior. A safe storage option is an airtight container with a lid equipped with a rubber seal. High-quality freezer containers are suitable for storage.
Note: It will take several months to get rid of the plague again. Therefore, make sure that your supplies are stored in an absolutely airtight manner.
Profile
The dried fruit moth is beautifully colored
The dried fruit moth (Plodia interpunctella) is a species of butterfly from the borer family. It is considered a pantry pest and attacks various foods in households and department stores. The species was introduced to Central Europe and spreads optimally in warm temperatures.
More common names:
- Copper-red dried fruit moth
- Store moth or house moth
- incorrectly the cocoa moth, behind which the species Ephestia elutella is hidden
Appearance
The adult butterflies have a wingspan between 13 and 20 millimeters. Their body is around four to ten millimeters long. In contrast to flour and cocoa moths, dried fruit moths are more conspicuously colored. Their forewings appear copper-red on the upper side with a creamy white zone in the front third, which is highlighted by a black band. When the moths are at rest, this area looks like a white shoulder. The underside of the forewings is silver-grey in color. The hind wings also have a grayish color.
| Coloring | Size | Other | |
|---|---|---|---|
| Egg | white with net-like pattern | about 0.5 x 0.3 mm | sticky |
| Larva | whitish, greenish, reddish with brown head | young: up to 1.5 mm, adult 14 to 17 mm | Coloring depending on food |
| Doll | white | 6 to 8 mm | dense silk cocoon |
Mating and laying eggs
Just a few hours after hatching, males mate with their sexual partners, who lay eggs a short time later. Females lay between 200 and 400 eggs, which are placed individually in a specific substrate. The eggs are not laid all at once but in several stages, with daily rates decreasing rapidly. Under optimal conditions, eggs are laid several times a year.
Excursus
Maggots and caterpillars
Caterpillars hatch from the eggs of the dried fruit moth. They represent the actual feeding stage of the butterflies, because many adult butterflies can no longer eat. The larval stages of butterflies are called caterpillars. Unlike maggots, which are the larval stage of dipterans, caterpillars have a head capsule and true limbs.
Lifecycle
After about a week, the caterpillars, which can be different colors, hatch. They feed mainly on the outer layers of the food and continuously develop fine webs. They go through several molts during this feeding phase. The number of these development phases varies between three and seven depending on the environmental conditions, with five larval stages being typical.
Shortly before pupation, the larvae stop eating and enter a wandering phase. They abandon the food supplies and look for a sheltered place where they can transform into a chrysalis. The hikes can last between three and ten days. Caterpillars pupate in crevices and sheltered niches. In the cocoon, the larvae can enter a dormant state that can last up to 330 days. This condition is called diapause.
This is how diapause occurs:
- falling temperatures
- Lack of light
- high population densities
| Development in the egg | Larval development | Development in the doll | |
|---|---|---|---|
| 20 degrees Celsius | 8 days | 50 days | 16 days |
| 25 degrees Celsius | 5 days | 28 days | 9 days |
| 30 degrees Celsius | 3 days | 20 days | 7 days |
Ecology and occurrence
Although the larvae of dried fruit moths depend on certain environmental conditions for optimal development, the caterpillars can also survive suboptimal conditions for a short time. To do this, adult caterpillars go into a state where they slow down their metabolism and no longer eat food. Only when the factors become more favorable again will the development processes continue.
Temperature
The larvae can survive cold temperatures for short periods of time, allowing them to survive in unheated storage areas. Even sub-zero temperatures in the upper double-digit range do not harm the organisms. If the temperatures fall below minus ten degrees Celsius, the larvae also die. If the thermometer rises to more than 30 degrees Celsius, the activity of the caterpillars also reduces. The optimal temperature range is between 20 and 30 degrees Celsius.
Moisture
The lifespan of the butterflies increases when the humidity increases. Therefore, dried fruit moths can often be observed in damp storage rooms. Puddles of water also promote the survival of the butterflies. Caterpillar development is also promoted by high relative humidity. It runs faster at values between 50 and 90 percent. The larvae survive even very dry conditions with humidity up to 20 percent.
Light
The moths are primarily active at dusk, where they are attracted to light sources and buzz around them. During the day they sit on the walls with their wings folded. The development of the larvae is influenced by the daily amount of light. Short periods of brightness cause a sleep state.
Spread
The dried fruit moth originally comes from warm, temperate and subtropical regions. Their main distribution area extends from the Near East to the Mediterranean region. Here the larvae develop on tree fruits such as figs, dates or apricots. The species has been introduced into numerous countries outside the natural range. Because of its high food tolerance and high adaptability, the dried fruit moth is the most common food moth.
Food
Adult dried fruit moths do not feed on food. Only the caterpillars pose a danger to supplies. The females lay their eggs on the food substrate so that the hatched larvae can spread immediately. They have a wide range of food and mainly attack carbohydrate-rich grain products and seeds. Even paper and plastic films are no obstacle for them because they can eat their way through the material.
This is what caterpillars eat:
- Chocolate: preferably with almonds and hazelnuts
- Nuts: trail mix, pistachios
- Grain products: pasta, muesli, bread
- Seeds: Legumes such as chickpeas, millet
- Stimulants: coffee, tea, cocoa
- Fruit: in exceptional cases fresh apples, peaches or dates
Frequently asked questions
How do I recognize a dried fruit moth infestation?
You can recognize a dried fruit moth infestation by the fact that various foods are covered in a fine white web. The pests prefer to live in damp pantries, but can also cope with drier conditions in kitchens. If you notice moths in your bedroom or on your clothes, it is probably the clothes moth (Tineola bisselliella).
How to distinguish food moths:
- Dried fruit moths are predominantly brown-white in color
- Flour moths have silvery-gray wings
- Mealborers appear brown-yellow
How can I find a dried fruit moth nest?
If you have disposed of infected food, you should store intact food airtight in freezer containers with rubber seals. Then search the rooms thoroughly. After the feeding phase, larvae retreat into niches, cracks and cracks and pupate there. Occasionally the caterpillars can survive under the floor covering and overwinter in the pupal stage. The caterpillars travel long distances between the food source and the pupation site, allowing them to spread throughout the house.
How long do dried fruit moths live?
The lifespan of the butterflies depends heavily on the temperature. Butterflies survive for about two to three weeks at room temperature. They need warm temperatures so that larvae hatch from the eggs, and subsequent development is also favored by rising temperatures. The warmer it is, the faster the organisms develop in the egg, larval and pupal stages:
- 20 °C: development takes 74 days
- 25 °C: development within 42 days
- 30 °C: development is 30 days
Where do dried fruit moths come from?
Dried fruit moths are introduced through contaminated food. Egg clutches are often found in animal feed. Under optimal conditions, the larvae hatch and spread en masse throughout the home. Cereal products are often infested, although the caterpillars have a wide range of food and can also appear in other dry foods.
Are dried fruit moths harmful to he alth?
Usually there is no need to worry if you accidentally consume infected food. Although the larvae are not poisonous, they do contaminate the food. They leave behind fine droppings on which fungi can settle. The spread of mites cannot be ruled out. Consuming contaminated products can cause problems for sensitive people such as allergy sufferers or asthmatics. As a precaution, discard affected and seemingly intact food.
