The University is working with arachnid experts and a pest control company to contain and reduce the population of Chilean recluse spiders as far as possible and ideally to eliminate it. The safety of people on campus and animals in animal housing shall be ensured at all times.
Staff, students, visitors, and contractors have been informed of the presence of this spider species and made aware of the risks.
Measures to control the infestation have been tailored to the specific rooms and their intended use. The spiders are held in check mechanically (cleaning, vacuuming), physically (dry steam, silicate powder), or chemically (acaricide). The effectiveness of these measures is being continuously observed and monitored. Monitoring is also taking place in adjacent areas that have not yet been affected.
The measures have already been implemented in the building at Hölderlinstr. 12 / Sigwartstr. 10. The lessons learned are now being applied to the affected buildings at the Morgenstelle Campus, where appropriate measures are also being taken.
The individual measures are described in more detail below:
Monitoring
For monitoring purposes, small black boxes with adhesive surfaces on the inside are distributed throughout the areas. These are checked regularly. Sightings are recorded.
This is to assess the effectiveness of control measures and to monitor the spread of the infestation. Future measures are planned based on the results of the monitoring.
Vacuuming
Industrial vacuum cleaners purchased specifically for this purpose make it easy to remove the spiders. Live spiders are usually killed instantly by the high suction power. Anyone can use these vacuum cleaners. However, this method is only effective in the moment; it is not a long-term solution.
You can borrow vacuum cleaners at the following locations:
- A Building: CZI Metal shop in H Building, level 1 (room C22. Borrowing hours: Mon. – Thurs 7:30 am to 3:30 pm and Fri. 7:30 am to 12:00 noon)
- B Building: Level 1, “Mülllager” (room B1E04)
- E Building: Level 10, storeroom (room P26)
- F Building/ Isotope lab: Level 2 (room 2J16) For the control area only - please use other devices for use in other areas of F Building)
- Morgenstelle Lecture Center: Caretakers’ Office (room 2E05)
- ZMBP: Level 2, workshop (room 2P19)
- Hölderlinstr. 12: Basement utility room (S114) and top floor computer room (S552A)
You can collect/ order new vacuum cleaner bags at the Building Services Workshop (E Building, 7A11). Please dispose of full vacuum cleaner bags at the recycling center (waste code 180104).
Special cleaning
Special cleaning removes spiders and webs, deprives them of their food sources, and enhances the effectiveness of the cleaning agents applied to the area cleaned. During this cleaning, particular attention should be paid to corners, crevices, and areas that are often overlooked during routine cleaning.
Cleaning should take place in all affected areas: hallways, stairwells, offices, laboratories, workshops, storage areas, and utility rooms. To facilitate thorough and easy cleaning, users should keep these areas as free as possible of furniture and other objects.
Dry steam method
This method specifically targets spiders and their eggs using dry steam (180 °C). The hot steam destroys the eggs. Spiders at all stages of development are killed within seconds by the thermal shock.
No chemicals are used in this process. The dry steam method can therefore be used almost anywhere. The disadvantage is that it is effective only at that specific moment.
Spray with insecticide silicate powder
This method specifically targets spiders using silicate powder (also known as diatomaceous earth). The powder works purely through physical means: It kills spiders and insects by dehydration, absorbing their protective waxy coating. Without this coating, the creatures dry out and die within a few days. The powder can be used safely almost anywhere and remains effective for a long time. However, affected creatures may continue to move around for several hours or even days.
Products used: Aco.spray SI Plus and GreenRange DE (safety data sheets available from Occupational Health and Safety)
Notes on the products: Both products contain substances that may act as sensitizers with respect to skin allergens. However, this is primarily relevant to users. Because of the long interval between application and the next time the rooms are used, the risk is extremely low.
Insecticide/acaricide spray treatment
With spray treatment, an insecticide is applied in a targeted manner. The products have a broad spectrum of effectiveness against insects and spiders. Treatment is targeted at areas where the spiders are present and the surfaces they move across. Spraying is done only in affected, less sensitive areas such as hallways, stairwells, storage rooms, or utility rooms. The products take effect immediately and have a very long-lasting effect. Disadvantages include the slightly greater effort required during application due to safety precautions and the subsequent need to keep the rooms off-limits for a time.
Products used: Fendona 60 EC plus G and Detmol-mic (safety data sheets available from Occupational Health and Safety)
Notes on the products: Do not touch treated surfaces. Touching the surfaces reduces the product’s effectiveness; and importantly, Fendona 60 EC plus G can cause allergic skin reactions upon contact. Because the product is applied to corners and edges, as well as in some joints, cracks, and on baseboards in the rooms, contact is unlikely during normal use of the rooms.
Both products are suitable for use in residential, commercial, and public settings. They contain a pyrethroid, a synthetic insecticide. Pyrethroids are extremely fast-acting contact and stomach poisons that paralyze the spiders’ nervous systems, resulting in immediate death. Pyrethroids are known for their high long-term stability. Therefore, these products are specifically applied in areas where large numbers of spiders have been sighted.
Active ingredients in Fendona 60 EC plus G: alpha-cypermethrin, Chrysanthemum cinerariaefoliu m extract from open and mature Tanacetum cinerariifolium flowers, geraniol.
Active ingredients in Detmol-mic: 1R-trans-phenothrin and prallethrin.
