Biosecuring India against exotic bruchids: two decades of quarantine monitoring of grain legumes germplasm

The quarantine of 36,500 germplasm samples of various grain legumes with seed as a pathway imported into India during 1996–2015 was undertaken at ICAR-National Bureau of Plant Genetic Resources, New Delhi. As these plant genera are known to carry hidden infestation, seeds were screened through soft X-rays and bruchids infestation (Coleoptera: Bruchidae) was detected in 3175 samples (8.69% infestation). The quarantine measures resulted in interception of 25 bruchids on 40 hosts from over 40 sources/countries. Of the interceptions, 13 bruchids are not reported from India. These are Acanthoscelides obtectus in Cajanus cajan from CIAT (Columbia), Brazil, Italy, Nigeria; in Phaseolus vulgaris from Columbia, Italy, Mexico, Nigeria, Peru, Slovakia and USA; Vigna subterranea from CIAT (Columbia) and in Vicia faba from ICARDA (Syria), Iran, Iraq, Lebanon, Spain, USA; Bruchidius atrolineatus in V. mungo from Srilanka; in Vigna radiata and V. unguiculata from Italy, Nigeria, UK; B. murinus in V. faba from UK; Bruchus affinis in Lathyrus spp., from USA; B.atomarius in Vicia gathrnensis and B. dentipes in V. faba from ICARDA (Syria) in V. narbonensis from Afghanistan; B. ervi in Lathyrus sativus from Lebanon, Syria; in Lens spp., from several countries; B. rufimanus in V. faba from Afghanistan; B. tristiculus in Lens sp., and B. tristis in L. sativus from ICARDA (Syria); Callosobruchus rhodesianus in V. unguiculata from Nigeria and C. subinnotatus in V. subterranea from Ghana; Specularius erythreus in Cajanus cajan and Vigna radiata from Italy.

In addition, risk of various pests associated with the import of these crops has also been evaluated. All the infested samples were salvaged using suitable phytosanitary techniques/treatments viz., X-ray radiography and fumigation so as to make available the pest free material to researchers throughout the country. The success of plant quarantine in biosecurity of Indian agriculture is clearly indicated by the interception of a number of exotic pests in the imported grain legumes, of which 13 are not yet reported from India. These include the bruchids with wide host range which are critical as they could become invasive under suitable biotic and abiotic conditions. If not intercepted, these would have caused havoc to our country.