OECD 183. 5 -  Assays for testing efficacy of baits against cockroaches (Series on Testing and Assessment No. 183, Series on Biocides No. 5).

This test is intended to determine the effectiveness of products used to control cockroaches in enclosed spaces with products that contain active and attractive insecticides.

The test must be done with at least three replicas at different times and with different batches of cockroaches. The following species of public health importance can be used in Europe, North America, Australia and Asia: Blatella germanica (German cockroach), Blatta orientalis (oriental cockroach), Periplaneta americana (American cockroach), Supella longipalpa (brown cockroach or of bedrooms), or Periplaneta australasie (Australian cockroach, Hawaiian and Southeastern US). Of these, the German cockroach and the Oriental cockroach are the most prevalent in Europe. If specific baits are to be tested for a species, it must be used. If on the contrary they were going to try general bait for cockroaches, the two most prevalent species should be used (Blattella germanica and Blatta orientalis in Europe or Periplaneta americana as an example of large cockroaches, in North America Blatela germanica and Periplaneta americana). In case you want to use local cockroaches to reflect the conditions of the place, or when there are problems of resistance to insecticides, it should be indicated.

The baits contain one or more active insecticidal ingredients combined with a food or non-active attractant compound for cockroaches. The active ingredients are toxic with lethal action on all mobile stages, or growth regulators that are active against nymphal stages, so that according to the active components should choose one or other stages to perform the tests. Baits should be attractive and effective even when there are alternative sources of food, and should maintain their insecticidal activity, their consistency and attraction even in damp locations, such as kitchens, toilets or pipes.

The tests can be carried out in two types of test chambers: a) unicompartmental chamber, or b) bicompartmental chamber consisting of two compartments joined by a tubular connection, one of them intended for feeding, and another of them intended for its location.

The insects used in the tests are reared in the laboratory, and adults or nymphs from early, middle or late stages are used. In the test, different evolutionary stages can be used: 50 adult specimens (25 males and 25 females for any of the three species); a mixture of adults and late nymphal stages (40 nymphs, 20 adult males and 20 adult females for Blatella germanica, with slight variations in number for other species, or early nymphal stages (50 to 100, depending on the species chosen). For each of the three replications, the insects must adapt to the test space for at least 3 days or until the insects adapt to their habitat, without exceeding an established mortality rate. 8 weeks depending on the active ingredients used (classical insecticides, juvenile insecticides or inhibitors of chitin synthesis) The tests are carried out at a test temperature that depends on the weather conditions in which the product is to be used (19ºC to 35-40ºC), although the average temperature that can be used is 22 ± 3ºC and a relative humidity of 55 ± 10%, but it can be higher for products that are going to be used in wet areas. During the test water is supplied ad libiutum. Three test groups (replicates) should be made for each concentration of the product evaluated, varying the position of the baits in each replica. At least two controls of the evaluated product (bait without active substance and active substance without bait) and a positive control using a registered substance intended for the same purpose (two replicates) must be included. During the exposure time (21 days), dead and dying cockroaches should be determined and followed up for at least 7 days after the end of the test, providing them with water and normal feeding. Mortality is evaluated on days 1 and 2 and every 24 hours of interval until 21 days, determining it by sex, stage of development and location.

The realization of the test can be by the method of "no choice", in which an alternative food is not found, or by the "choice" method, in which an alternative food is available. The "no choice" method is recommended when you want to know if the bait matrix is ​​attractive to cockroaches, to detect repellency and the concentration of active ingredients in the formulation to kill the cockroaches. The method of "choice" is indicated to know the attractive effect in comparison with other alternative sources of food. To consider an effective product, a corrected 95% mortality rate in a "no choice" test or 90% in an "election" test must be obtained at the end of the test.

Variables to be selected by the applicant:

  • Concrete species to be used in case of specific baits of species, or more prevalent species in case of general baits for cockroaches.
  • Type of insecticide (classic, juvenile phases, inhibitors of chitin synthesis).
  • "No choice" or "choice" method.
  • Phases of insects that are to be used according to the activity of the insecticidal compounds containing the baits (adults, adults and nymphal stages, only nymphal stages).
  • Exhibithion time.
  • Ambient conditions of temperature and humidity in case they are unusual conditions (temperature 22 ± 3ºC, relative humidity 55 ± 10%).

Material provided by the applicant:

  • Complete baits, containing insecticidal and attractant substances.
  • Controls with insecticide substance, without attractant substance.
  • Controls of attractive substance, without insecticide component.
  • Registered positive control in case the manufacturer wishes to choose it.
  • Form with product characteristics and variables for testing.

Delivery of results

We cannot give an exact term since this depends on the time necessary to dispose of the adult insect specimens or in nymphal stages to be used in the tests, to which must be added the chosen exposure period (3 to 8 weeks), plus the 21 days of follow-up after the exposure.

Cost of the tests

Basic price: it is applied for a species of cockroach to choose between the three indicated; a type of population included; adults, adults plus nymphal stages or early nymphal stages; a test modality (“non-choice method” or "choice" method); a concentration of active substance chosen by the client (with three test replicates) with its corresponding controls with active substance without attractant (two replicates) and bait with attractant without insecticide component (two replicates); a positive control with a substance registered for the same purpose (two replicates); a time of exposure; a temperature and a relative humidity. For more variables consult price.