Annual Symposium of the Department ofAgriculture, Sri Lanka. 2:65-70. September 2000

PESTS DETECTED IN AGRICULTURAL COMMODITIES IMPORTED TO SRI LANKA

R. S. Y. DE SILVA and A. S. P. WEERASINGHE National Plant Quarantine Service, Canada Friendship Road K atunayaka

ABSTRACT

Plant quarantine officers at the two entry ports, Bandaranaike International Airport, Katunayake and the seaport of Colombo, have sampled the commodities of phytosanitary concern to Sri Lanka. These samples were inspected and tested by the National Plant Quarantine Service at Katunayake. Commodities included seeds, vegetative planting material, fresh fruits, plant material for processing^ and soil. More than twenty-seven species, seven plant viruses and plant parasitic nematodes belonging to nine genera were detected from the material. Three A2 pests of the Asia and Pacific Plant Protection Region, viz., Clavibacter michiganensis ssp. sepedonicus, Oospora pustulous (=Polyscytalum pustulous), and Phoma exigua var. forveata were detected from seed potatoes. Banana plants imported from India and Israel were infected with either one or two of the viruses, banana bunchy top virus, banana streak virus and banana bract mosaic virus. Codling , Cydia pomenella was isolated from apples imported from India. Among the insect pests detected, Cadra figuliella and ^gularis in cashewnut imported from Ivory Coast and Cryptoblabes gnidiella in pomegranate plants imported from India have not been reported to occur in Sri Lanka. Difficulties were encountered in the correct identification of certain pests like leaf miners, mites, mealy bugs, scale and plant parasitic nematodes. Eco-climatic conditions in the country are conducive for most of these pests. Considering the diversity of the material inspected and the pests detected, continued vigilance must be kept to intercept alien organisms entering the country.

KEYWORDS: Import cargo, Interceptions, Plant Quarantine, Quarantine pests

INTRODUCTION

Agricultural commodities are very effective carriers for international movement of plant pests, unless adequate preventive phytosanitary safeguards are adopted. Pests detected during inspection of imported cargo at the entry ports of a country indicate the possible invaders. Usually, plant quarantine services are expected to take necessary safeguards to negate the impact of the alien pests on agriculture of a country. Almost all countries keep records of pests intercepted at the entry ports from various commodities imported into their territory (Ahmed, 1991; Okawa, 1991; Ray, 1993).

In this paper the term “pest” is used in the sense of what is given in the Plant Protection Act (1924) of Sri Lanka. It means “any biotic agent capable of causing injury or damage or loss to plants or plant products and shall include weeds.” This paper reports the pests detected in commodities imported during last five years, which were of phytosanitary concern except plant pathogens and weeds associated with seed. 66 DE SILVA AND WEERAS1NGHE

MATERIALS AND METHODS

Samples from the commodities of phytosanitary concern to Sri Lanka were taken by plant quarantine officers at the entry ports (Bandaranaike International Airport, Katunayake and Colombo Seaport). The samples were submitted to the National Plant Quarantine Service, Katunayake for investigation. A team comprising of entomologists, nematologists and plant pathologists inspected the samples to determine possible pest infestations. The samples were first observed under the microscope. If a pest was detected, suitable culturing procedures were attempted depending on its nature. Virus detection was usually based on serology and sap inoculation into indicator hosts. Biochemical and serological tests were adopted for the identification of bacteria.

RESULTS

About 13 fungal and bacterial pests were detected during the review period (table 1). The majority was from seed potato imported for planting. Mango fruits imported illegally from Pakistan and arecanut imported from Indonesia had bacterial pathogens. Several viruses were detected in imported banana and orchid plants (table 2). Twelve lepidoteran pests, 11 coleopteran pests, two dipteran pests were intercepted from several commodities (table 3). Rooted plants imported had several species of nematode pests (table 4). Illegally imported soil from the Maldives, had a very high nematode population. Leaf miners, mealy bugs, scale insects and thrips were often detected but their accurate identification was difficult (table 5).

Table 1. Fungal and bacterial pests detected in plant material imported during 1994/1999.

Pest Commodity Country o f origin Alternaria solani Seed potato Holland Clavibacter michiganensis ssp. sepedonicus Seed potato Holland Corticium rolfsii Seed potato Australia Erwinia chrysanthemi Arecanut Indonesia Erwinia sp. Seed potato Holland Geotrichum candidum Seed potato Holland Lasiodiplodia theobromae Mango fruits Pakistan Oospora pustulans Seed potato Australia Phoma exigua var. forveata Seed potato Australia Phoma sp. Seed potato Australia Phomopsis sp. Seed potato Australia Phytophthora palmivora Mango fruits Pakistan Xanthomonas campestris pv. arecae Arecanut Indonesia PESTS IN IMPORTED AGRICULTURAL COMMODITIES 67

Table 2. Plant viruses detected in the imported plants.

Pest Commodity Country of origin Banana bract mosaic virus Banana plants- India Banana bunchy top virus Banana plants India Banana streak virus Banana plants India Israel Carnation mottle virus Carnation plants Holland Cymbidium mosaic virus Dendrobium sp. Thailand Oncidium sp. Thailand Odontoglossum ringspot virus Dendrobium sp. Thailand Tobacco mosaic virus Oncidium sp. Thailand

Table 37 Insect and mite pests detected during 1994-1999 in imported agricultural commodities.

Pest Commodity Country of origin Agrotis segetum Gladiolus India Gypsophila India Ahasverus advena Cashew nut Ivory coast Alphitobius diaperinus Cashew nut Ivory coast Sesame seeds China Bactrocera dorsalis Mango fruits India Mango fruits Pakistan Persimmon fruits Pakistan Bactrocera zonata Mango fruits Pakistan Mango fruits India Cadra cautella Cashew nut Ivory coast Cadra figuliella Cashew nut Ivory coast Carpophilus hemipterus Cashew nut Ivory coast Corcyra cephalonica Cashew nut Ivory coast Cryptolestes sp. Sesame seeds China Cryptoplabes gnidiella Pomegranate plants India Cydia pomenella Apple fruits India Lasioderma serricorne Pimento seeds Australia Latheticus oryzae Cashew nut Ivory coast Paralipsa gularis Cashew nut Ivory coast Plutella xylostella Cauliflower India Chinese cabbage India Rhizoglyphus sp. Arecanut Indonesia Rhizopertha dominica Rice seeds India Wheat seed - USA Sitophilus sp. Cashew nut Ivory coast Rice seeds The Philippines Sesame seeds China Wheat seeds USA Spodoptera exempta Chrysanthemum plants Singapore Spodoptera litura Capsicum fruits' India Spodoptera sp. Cauliflower India Chinese cabbage India 68 DE SILVA AND WEERASINGHE

Table 3. Continued Sternochetus m an gif era e Mango fruits India Mango fruits Pakistan Tenebroides mauritanicus Cashew nut Ivory coast Tetranychus sp. Apple fruits China Tribolium castaneum Cashew nut Ivory coast Pimento seeds Australia Wheat seeds USA

Table 4. Plant parasitic nematodes detected in imported agricultural commodities during 1994-1999.

Pest Commodity Country of origin Aphelenchus avenae Jasmine plants Jordan Soil The Maldives Gracilacus sp. Orange plants Pakistan Helicotylenchus sp. Ficus plants India Grass plants India Pomegranate plants India Pomegranate plants Unknown Meloidogyne sp. Cactus plants Thailand Pratylenchus sp. Carpet grass seeds India Radopholus similis Anthurium plant Thailand Rotylenchules sp. Guava plants M alaysia Trichodorus sp. Olive plants Italy Tylenchorhynchus sp. Olive plants Pakistan Xiphinema sp. Palm plants India Soil The Maldives

Table 5. Plant pests that were not identified.

Pest Commodity Country of origin Leaf miners Citrus plant Malaysia Guava plant Malaysia Orange plants Pakistan M ealy bugs Citrus plant Malaysia Guava plant M alaysia Mango fruit India Pomegranate fruit India Mites Arecanut Indonesia Gladiolus India Grass seed Thailand Pentatomidae bug Capsicum fruits India Plant parasitic nematodes Date palm plants Kuwait Grapevine plants Jordan Orange plants Pakistan Orange plants Oman Carambola fruits Australia Scale insects Grapes fruits India Mango fruits India Oranges fruits Australia Jasmine plants Jordan Thrips Gladiolus India PESTS IN IMPORTED AGRICULTURAL COMMODITIES 69

DISCUSSION

Three pests, viz. Clavibacter michiganensis ssp. sepedonicus, Oospora pustulans, and Phoma exigua var. forveata detected in seed potato were considered as A2 pests by the Asia and Pacific Plant Protection Commission. These were not reported to occur in Sri Lanka. Additionally, G eotrichum - candidum has special phytosanitary concern to Sri Lanka during the import of seed potato. This is a pathogen affecting several economic crops and the most serious devastation occurs with Citrus spp. It is also pathogenic to including man (Holliday, 1980). f or EPPO countries, Erwinia chrysanthemi is a plant quarantine pest (Smith et al., 1992), and it can infect several plants with economic importance to Sri Lanka. If it establishes in the country, export of certain commodities like flowers, foliage plants to Europe will be affected. Out of the insect pests intercepted, Cadra figuliella, Cryptoblabes gnidiella and Paralipsa gularis have not been reported to occur in the country.

The two fungi, Lasiodiplodia theobromae and Phytophthora palmivora, intercepted from mango fruits imported illegally from Pakistan were of little phytosanitary concern to Sri Lanka. The fruit flies, Bactrocera dorsalis and B. zonata detected have been found to occur in Sri Lanka. Several other pests such as Plutella xylostella, Spodoptera exempta, S. litura, Tribolium castaneum etc. are also reported to occur in the country even though they are serious pests.

Within the last few years, the country experienced new pest invasions, which caused economic damage to crops. They included a mite (Aceria guerrerensis) attacking coconuts, a leaf miner (Liriomyza huidobrensis) on vegetables, grassy shoot MLO on sugarcane etc. Special plant protection regulations had to be implemented for the control of some of these pests. Large consignments of commodities imported were destroyed due to unacceptable levels of pest infections. On several occasions, even the exporting country has refused to accept the consignment if reshipped without proper treatment against the pest found.

Dependence on the symptoms and or visible damage done to plant parts for identification of a pest is not a good criterion for plant quarantine (Kahn, 1989). Often the pest may be latent or hidden in some parts of the material imported that makes the detection difficult. The unavailability of expertise on accurate identification of pests like mites, leaf miners, nematodes etc. create problems in trade. Lack of proper identity of a pest intercepted prevents the analysis of the risk involved. 70 DE SILVA AND WEERASINGHE

CONCLUSION

Plant quarantine officers were able to identify several dangerous pests found in imported agricultural commodities. Most of these commodities were not allowed to enter into Sri Lanka. However, there were many pests that could not be properly identified.

ACKNOWLEDGEMENTS

The authors wish to thank the staff of the National Plant Quarantine Service for their dedicated work during the identification of pests. The authors also wish to express their appreciation to Dr. S.M.C. Subasinghe and Mr. K. Hettiarachchi for the constructive criticism on the manuscript.

REFERENCES

Ahmed, S.A. 1991. Pest intercepted during July to September 1991 at ports of entry in Pakistan. FAO Quarterly Newsletter, Asia and Pacific Plant Protection Commission. 34(3-4): 7-8.

Holliday, P. 1980. Fungus diseases of tropical crops. Cambridge University Press, Cambridge. 607 p.

Kahn, R.P. 1989. Plant protection and quarantine, vol I. Biological concepts. CRC Press, Inc. Boca Raton, Florida. 226 p.

Okawa, Y. 1991. Records of interception of oriental fruit fly, Dacus dorsalis Hendel, at the import quarantine inspection at airports in Japan. FAO Quarterly Newsletter, Asia and Pacific Plant Protection Commission. 34(3-4): 4-6.

Ray, C. 1993. Pest of quarantine significance intercepted at various ports of entry in India during July-December 1993. FAO Quarterly Newsletter, Asia and Pacific Plant Protection Commission. 36(3-4): 3.

Smith, I.M., D.G. McNamara, P.R. Scott and K.M. Harris. 1992. Quarantine pests for Europe. C.A.B. International, Wallingford, UK.