MULTAN, Aug 24 (APP): An insect called ‘Assassin Bug’ is being nurtured by the Entomology Department of the Central Cotton Research Institute (CCRI) Multan in its laboratory.
Entomologist Dr Rabia Saeed, who is overseeing the research, says the predator feeds on over 20 major cotton enemy pests, including dangerous bollworms, which, besides reducing expenses on insecticides, will be an invaluable addition to the armory of farmers, especially those who wish to embark on organic cotton production.
“The enemy insect pests cause almost 46 per cent damage to the crop production and the CCRI Multan researchers are busy in surveys looking for some alternate options like friendly pests to lessen or completely control the damage caused by insect pests. It becomes more important in a scenario where efficacy of insecticides or pesticides is not up to the mark and cannot be fully relied,” the entomologist adds in a video posted on the youtube channel CCRI Cotton News.
Dr Rabia said studies on the predator were also carried in other countries, however, in Pakistan the CCRI Multan took the lead in launching the study to benefit the farmers.
“This Assassin Bug, scientifically called Rhynocoris marginatus is usually found in cotton, Okra, groundnut and pigeon pea fields in Asia,” she said, adding the predator was collected from the Swabi district of Khyber Pakhtunkhwa and now being nurtured in the CCRI’s laboratory.
“The laboratory results show it successfully feeds on armyworm, pink bollworm larvae and Dusky Cotton Bug,” she added.
Dr Rabia said the predator was released in some select cotton fields. They were also planning a trial on two cotton fields at the CCRI farm, one to be equipped with the Assassin Bug and the other with no Assassin Bug to assess its efficacy against the enemy pests and to know whether it also feeds on other crop friendly pests.
It may be noted that the Punjab government’s laboratories have also been nurturing friendly pests like Chrysopa since long and advocating Integrated Pest Management (IPM) technology for cotton.
Dr Rabia explained that “the Assassin Bug is attracted to the enemy insect pests by the pheromones emitted by the latter and then eat them. However, in case, it does not find enemy pests, the predators will start attacking one another to meet their food requirements and this phenomena is called as canabalism”.
CCRI Multan’s Transfer of Technology Department head Sajid Mahmood said there were 150 reported cotton enemy pests in Pakistan, the most among the cotton producing countries.
Another scientist Dr Farhan Ahmad declared the Assassin Bug to be the most effective general predator against cotton enemy pests and said that given the number of enemy pests, the probability of predators finding no enemy pests was extremely low.
“The Assassin Bug is nowadays under study and will be available for farmers once its population is increased to required level and a set of recommendations is prepared on how and when it should be released in the cotton fields to kill enemy pests,” he added.
Biocontrol agents against cotton insect pests, especially those of pink bollworm and armyworm were explored by the scientists of CCRI Multan to mitigate economic losses and discouraging indiscriminate use of insecticides. One male and two females of Rhynocoris marginatus, (Hemiptera: Heteroptera, Reduviidae: Harpactorinae), a potential predator of many insect pests, were collected from Swabi district of Khyber Pakhtunkhwa. Sufficient mass production under special care was established on armyworm, pink bollworm, cotton stainer and grain moth (Sitotroga cerealella), however, evaluation of different formulations of artificial diets is still in progress.
Augmentative releases are planned to be made in the upcoming cotton season (2023) to induce insecticidal and heat resistance ability by direct exposure to the predator and assessment of its bio-control efficacy in the field, according to a brief from scientists.
It feeds on more than 20 major insect pests particularly lepidopteran larvae. These are attracted by kairomones emitted by prey. A female can lay 315-414 eggs in 6-8 batches during its life. Total life of female from egg to adult ranges from 148-175 days that fluctuates depending upon temperature and prey resource value.