What were the results of the EPA evaluation on safety of Aprehend®?
The EPA summary on risk to human health is as follows:
When applied as a pesticide to control bed bugs indoors, EPA concludes that use of Beauveria bassiana GHA will not result in unreasonable adverse effects to humans. The new use will not contribute to oral exposures already evaluated for the agricultural use. EPA does not expect dietary (food and drinking water) or other non-occupational risks from the indoor use of B. bassiana GHA as an active ingredient in Aprehend®. The incidental dermal/inhalation exposures from indoor use will be limited. Any occupational exposures to applicators handling B. bassiana GHA are expected to be minimized by label precautions and the use of the required PPE; which in addition, addresses the general concern for potential allergic sensitization for all microbial pesticides. It is not appropriate to aggregate dietary risk of other B. bassiana GHA products with the risks of dermal sensitization from Aprehend® since the endpoints are different.
(Regulatory Decision for the First Indoor Use of the Active Ingredient Beauveria bassiana strain GHA to Control Bed Bugs. Richard Kegwin, Office of Pesticide Programs, US EPA 02/15/2017)
Does Beauveria have a safety record?
Beauveria bassiana is a fungus that is commonly found in the environment, particularly soils in the US and throughout the world. People are constantly exposed to low levels of fungal spores, including Beauveria spp. on a daily basis. In fact, the commercial product Botanigard®, which also contains the same GHA strain that is in Aprehend®, has been used to control pests in vegetable products in the US and worldwide for the past 20 years. Products can be sprayed with Botanigard® (Beauveria GHA) on the day that they are harvested and sent to the store. It's likely that the tomatoes in your home refrigerator have been sprayed with Beauveria (GHA) spores prior to harvesting, particularly if they are organic. Because of its long-standing and widespread use, Beauveria GHA already has an outstanding safety record.
What about people with compromised immune systems, and other medical issues?
A complete and thorough search of the scientific literature resulted in the identification of just seven reports of human infection by 'Beauveria' species worldwide. In all reports, the patient was immunocompromised and the specific source of the infection was unknown. In ALL cases the infection was successfully treated with routine antifungal medication, with no further repercussions. However, there have been NO incidents of human infection attributed to commercial isolate GHA, which has been in widespread use for the past 20 years. This absence of any negative human effects attributed to the GHA isolate is significant. Even Saccharomyces cerevisiae (Brewer's/Baker's yeast), considered to be the least dangerous fungal species, has been found to be responsible for invasive, infection in immunocompromised patients in 72 published cases.
While it is clear that no pesticide should be considered completely safe, the risk associated with the use of Aprehend® according to label instructions is extremely low.
What about allergy sufferers?
Allergic responses can be triggered by the inhalation of any proteinaceous dust, these include fungal spores, pollen, insect skin fragments, animal dander etc. The fungal spores in Aprehend® are formulated in a proprietary oil formulation, which is designed to stick the spores to the surface where they are applied. The Aprehend® label requires that residents do not re-enter their property for 4 hours after treatment. This ensures that all aerosolized droplets will have settled. Once applied, the spray residue sticks to the surface and will not become airborne again, so there is no risk of inhaling fungal spores, providing the label instructions have been followed. Aprehend® is applied to areas where human contact is likely to be minimal; this helps to ensure the spray barrier remains in place and is effective for up to three months. Even direct skin contact with the spray residue is unlikely to cause any adverse or allergic response.
Will customers be put off by the idea of fungus being sprayed inside their homes?
As we know, 'fungus' means different things to different people. Many fungi are used in food products such as cheese - Brie, Camembert, and blue cheeses (Penicillium spp.), quorn™- fungal protein-based meat alternative (Fusarium sp.), soy sauce (Aspergillus sp.), and of course edible mushrooms (Agaricus, Lentinus, Pluerotus).
Beauveria bassiana causes disease in insects. Interestingly, Beauveria infected silk worm larvae have been used Chinese medicine for centuries. Infected larvae are eaten whole or ground into powder and consumed, to cure a range of intestinal and liver complaints.
Essentially, it's all about the perception and while they describe the same thing, using a 'natural disease of insects' may sound more palatable than 'fungus spores.'
Can the fungus grow inside people’s houses – particularly damp ones?
Beauveria cannot and will not grow in people's houses. Under normal humidity conditions, it will not even germinate unless it is in contact with a bed bug. At very high humidity (>90%), the microscopic spores in the spray residue may germinate, but no visible growth will occur, and the spore will just go on to die because it has no food source to utilize. Typical mold fungi (Aspergillus and Penicillium) have specific enzymes that allow them to break down cellulose and lignin and are adapted to growth in structural environments. You can see these fungi because they grow and produce new spores (the green coloration) using the wood or plasterboard as a food source. Beauveria does not produce these enzymes and cannot grow in these environments.
If Aprehend® is non-toxic, how does it kill bed bugs?
The fungus in Aprehend® is an infectious agent, not a toxin; it kills by penetration of the insect cuticle and growth inside the blood system (hemocoel) of the bed bug. The fungus is not infectious to humans, as it is a specialist insect pathogen. It cannot grow at human body temperature.
Has Aprehend® been tested on humans?
No, human testing is never conducted on pesticide products. There are a specific set of animal test protocols that are required by the EPA, and these were part of the regulatory dossier submitted for Aprehend®.
Human testing is only conducted on drugs for treating human diseases; the US Food and Drug Administration (FDA) regulates these. However, commercial use, and resulting human exposure to the GHA Beauveria strain in the US, South America and Europe over the past 20 years, has resulted in no reported adverse human health effects. GHA cannot grow at human body temperature (98°F). The EPA assessment of Beauveria is that it poses a very low risk to humans when used according to label instructions, in both horticultural and domestic environments.
What about the signal words – Caution and Danger?
The Aprehend® SDS uses the signal word 'Danger' because some of the components of the oil formulation are 'Petroleum Distillates.' These products should not be inhaled. For this reason, respiratory protection must be worn during application of Aprehend® and residents should not re-enter areas where application has taken place for 4 hours. This ensures that all spray droplets have settled and no longer pose an inhalation risk. Occasionally it is possible to see a spray 'mist' during application of Aprehend®; this mist is comprised of tiny aerosolized oil droplets, which will settle within three hours of application. Always check that your application speed and distance from the target surface are correct. Spray application, at a distance of 3-4” and a speed of 4-5 seconds per yard, will provide the most efficient application and minimal spray mist formation.
Chemical vs. biological risk
In theory, there should be no difference in the health risks associated with the use of either chemical or biological pesticides when used according to label instructions. However, we have to accept that there will be occurrences where products may not have been applied appropriately. The negative health effects associated with chemical pesticides include, dermatological, gastrointestinal, neurological, carcinogenic, respiratory, reproductive, and endocrine effects. High occupational, accidental, or intentional exposure to pesticides can result in hospitalization and death.
While chemical pesticide residues from appropriately applied products do not exceed the legislatively determined safe levels, these may underestimate the real health risk if simultaneous exposure to pesticides from two or more sources occurs (e.g. from chemical application inside the home, and via residues on food products). Often, the effects of chemical pesticide exposure can go unnoticed, but the long-term effects can result in significant health impacts.
Conversely, due to its non-toxic nature, cumulative exposure to biological products such as Aprehend® via different sources, would not increase the risk of health impacts.