Sri Lanka: Khapra Beetle — alarmist scientists must stick to facts

The khapra beetle is a pest that feeds primarily on grain. It has never been associated with tea. It follows that it poses no threat to the tea industry.

by Rohan Pethiyagoda-Dec 29, 2017

( December 29, 2017, Colombo, Sri Lanka Guardian) I was surprised and disappointed to read the article “Khapra beetle and future of Sri Lankan Tea Export” by Professor Rohan Rajapakse and Dr Wolly Wijayaratne in ‘Sri Lanka Guardian’ of 19 December. I would not normally respond to such an article except that this has found itself widely circulated also on the internet and social media, as scaremongering claims so often do, with potential harm to the integrity of the Ceylon Tea brand.

These authors have cushioned their article with a wealth of technical-sounding data. A quick perusal of the internet suggests one might be forgiven for imagining them to have been also the authors of the Wikipedia entry on khapra beetle. Their academic distinction, however, may give less-well informed readers the impression that somehow they know something about this subject that others do not. I, for one, doubt that.

They state, “Khapra beetle has been sighted on several occasions in Sri Lanka” (evidently by persons other than themselves). They then go on to cite a series of references to the scientific and grey literature (i.e. circulars, reviews etc). None of the scientific publications they cite are more recent than 1977; i.e., they are more than 40 years old. The National Plant Quarantine Service maintains, however, that no infestation by this beetle has ever been recorded from within Sri Lanka, and certainly not in the career-span of anyone working there today. The Department of Agriculture too, has no record of detecting this species in Sri Lankan agricultural produce.

Rajapakse and Wijayaratne base their claims on an antiquated literature, mostly in very obscure publications. Even if antiquated, these historical records warrant review, and so I reviewed almost all of them. I was unable to uncover, however, whether in the publications cited or elsewhere, a single specimen-based record of khapra beetle from Sri Lanka. Not ever. Period. The question I pose to these ‘experts’ therefore is, have you even seen a specimen? A specimen collected in Sri Lanka is, after all, the only acceptable evidence that the species occurs here.

I looked also into how Sri Lanka might have become included among the countries which this notorious pest was previously claimed to inhabit. A close reading of the very same references that Rajapakse andWijayaratne have cited shows that no specimen-based location record for Sri Lanka is claimed by any of the authors concerned. In general, given that India is the putative “home” of this species (its native range remains uncertain) and given Sri Lanka’s proximity to India (especially the inclusion of Ceylon in the loose wording “British India” in colonial times) it appears to have been assumed that Sri Lanka too, fell within the range of this species. Other studies have sought to predict the regions of the world which could host this beetle by modeling the relevant environmental criteria (e.g. rainfall, humidity, temperature, longest dry period etc). Clearly, Sri Lanka would be among the countries that are at risk of hosting this species. That is a far cry, however, from claiming that the beetle actually infests Sri Lankan crops or is naturalized in the island. As so often happens in the scientific literature, and especially in non-specimen based studies, the errors of the earlier authors tend to be repeated uncritically ad infinitum by later authors. Rajapakse and Wijayaratne too, appear to have fallen victim to this error. Neither of them admits to have seen a specimen of khapra beetle from Sri Lanka. Even the photograph of the beetle with which their article has been illustrated has not been taken by them: it has been downloaded from the internet. All this calls into question their pontifications and prognostications on this topic.

The khapra beetle is a pest that feeds primarily on grain. It has never been associated with tea. It follows that it poses no threat to the tea industry. Therefore, the authors’ statement that “it is up to experienced entomologists to find workable solutions to exclude the presence of khapra beetle in tea” is a nonsense. It is also important to note that the detection made by the Russian Federal Service for Veterinary & Phytosanitary Surveillance is stated to have been of khapra beetle larvae in the shipping container carrying the tea, not in the tea itself. It is possible that this container contained grain residues from a previous voyage originating in another country and was already infested with beetle larvae when the tea was loaded. If true, this is by itself, of course, unacceptable. As a response to such a threat, however, we have assured the Russian authorities that in future the containers in which shipments of agricultural produce are made to Russia will be professionally cleaned and disinfested under the supervision of the National Plant Quarantine Service. The Russian side has accepted this assurance, which will be reflected also in the relevant phytosanitary certificates.

That said, as a rice-producing country, Sri Lanka needs to be vigilant with regard to this pest. The absence of evidence is not evidence of absence. Pheromone traps and other detection methods need to be deployed to satisfy ourselves that this species is not becoming established in Sri Lanka, and stringent inspections of imported grain need to be conducted to minimize the risk of infested produce entering the island. I have no doubt that the NPQS will, as it has done so effectively for decades, continue to do its job professionally and effectively.

I was surprised to see that the lead-author of this article claims to be a member of the Technology Release Committee of the Tea Research Institute, which suggests that his views may somehow reflect those of the TRI. I would be astonished if this were indeed the case, but if so, it a poor reflection indeed of that august institution.

The internet era has made it possible for anyone with time on their hands, be they ever so ignorant, to publicize alarmist stories. As purportedly reputed scientists, Rajapakse and Wijayaratne had a responsibility to be more circumspect about publishing unsubstantiated claims in the popular media. There may be a time for this, but that time was certainly not the day after the Russian restrictions on tea exports came into force, even as negotiations to have them lifted had only just commenced. Tea exports to Russia are crucial to the wellbeing of the hundreds of thousands of stakeholders of the Sri Lankan tea industry. This incident could well have resulted in a protracted export ban with the gravest economic consequences for our country. As it was, a catastrophe was averted only by the swiftest action at (in alphabetical order) the diplomatic, official, political and technical levels of government. One need only peruse the internet to see the devastating impact that protracted bans on agricultural-produce imports by the Russian Federation have had on other countries, including ones with much greater economic and diplomatic clout than Sri Lanka possesses.

What purpose could Rajapakse and Wijayaratne’s scribblings have served but to spread alarm and worsen our chances of swift remedial action? Some might think they were merely trying to set themselves up as the experts to whom the nation should turn in its hour of crisis, but I for one wouldn’t ascribe such base motives to two such well-established academics. Nevertheless, their article, embellished as it was with their elaborate “scientific” credentials, and taken together with the attention it attracted on the internet, risked seriously jeopardizing the negotiations that led to the lifting of the ban. I am grateful that it did not. It is regrettable, nevertheless, that they chose to go where angels fear to tread notwithstanding the greater interests of our country and its people.

( The writer is the Chairman, Sri Lanka Tea Board )