An Agricultural "Ellis Island"

George G. Becker.

Within the Port of New York, at 209 River Street on the Hoboken, N. J., waterfront, is a four-story brick building where the Department of Agriculture fulfills a function of protecting the plant life of this country.

In this agricultural "Ellis Island" the Government, so to speak, examines the passports of incoming plant material and inspects and treats it before it is turned loose for planting.

The mere arrival and handling of some prohibited categories of plant material may involve a risk of pest introduction. The shipper must be informed of these prohibited categories. He must also know of the restrictions dealing with size and age, packing, certification, and other details. To be provided with the necessary information to send his shipper, the prospective importer must therefore get his passport, or import permit, in advance of shipment.

When plant propagating material arrives at Hoboken it is under customs bond and remains so until all customs, plant quarantine, and other Government requirements have been met. Before the material is imported the importer will have, or should have, procured a permit for its entry and with it appropriate instructions to send the shipper and to provide for its orderly entry. All plants, cuttings, and seeds and certain bulbs are required to move under customs bond to the designated inspection station, where they remain under customs custody until the customs have determined that all requirements are satisfied.

The inspection station at Hoboken is kept locked at all times. Importers are not allowed to see or know what their competitors import or where they get what they import. All windows are screened. Walls, floors, and ceilings where plant material is stored, inspected, or handled are of tile construction and can be disinfected readily. Ceilings, screens, and walls are sprayed often so that insects that escape from imported material will be knocked down when they alight upon treated surfaces.

Incoming material, arriving on the first floor, is stored apart from material that has cleared quarantine. On the second floor, material is inspected in one of two rooms, a large inspection room where large cargo shipments are handled, and a smaller room where mail and other small shipments are inspected. Besides the quarantine station at Hoboken, where most of the propagating material is handled, there are stations at San Francisco, Seattle, Miami, Laredo, Tex., San Juan, P. R., and Honolulu. The material that enters from Europe must clear Hoboken. The plants that arrive at the stations in San Francisco, Seattle, Laredo, and Miami are cleared there before being forwarded. The material may not move overland untreated.

These stations are operated by the Bureau of Entomology and Plant Quarantine. The Bureau of Plant Industry, Soils, and Agricultural Engineering maintains plant introduction stations at Glenn Dale, Md., Savannah, Ga., Coconut Grove, Fla., and Chico, Calif., and regional stations in cooperation with the States at Ames, Iowa, Experiment, Ga., and Pullman, Wash. At them, valuable importations of otherwise prohibited material are grown under quarantine until they are released by plant quarantine inspectors.

The inspection staff at Hoboken consists of entomologists, plant pathologists, and botanists. Besides their specialized knowledge, the inspectors must be well informed on the proper care of the valuable plant material in their custody as well as on methods of packing and forwarding. Inspectors take pride in the fact that material goes forward in as good or better condition than when it was received. Many shipments are reconditioned which, had they gone forward without passing through quarantine, would have been a total loss.

The inspectors must have the proper training to recognize plant pests. They must be able to identify plants and understand that some plants which may not be botanically related may nevertheless be tied together in a biological relationship to perpetuate an insect pest or plant disease. A native plant louse known as the woolly apple aphid uses our American elm as an alternate host. Therefore the American elm could be a means of introducing the pest into a new region. To protect the Nation's wheat industry the inspector must recognize species of barberry and closely related plants on which a stage of the destructive black stem rust of wheat develops. He must recognize species of currants, including our black currant, red currant, and many ornamental species. The black currant is an alternate host of a destructive disease, the white-pine blister rust, which attacks five-leaved pines. Many plants related to citrus must be recognized, as their entry is prohibited because of the possibility of introducing citrus canker.

To minimize the risk of introducing plant pests, the Department's Quarantine No. 37 imposes restrictions on the size and age of woody plants. The younger a plant the less chance it has had to become infested or infected with pests. The inspectors therefore must be able to determine whether plants offered for entry are within age limits. Another requirement is that woody material that can be grown from seed and will come true from seed may be imported only as seed. The eucalyptus trees of the west coast owe their picturesque shape to the fact that before the passage of the Federal Plant Quarantine Act of 1912, California horticultural authorities, profiting from previous experience, limited the introduction of eucalyptus species to seeds; thus they kept out a destructive beetle that eats the terminal buds and causes the development of trees of a bunchy growth. To enforce the no-woody-seedling requirement, inspectors must be able to distinguish between seedlings and plants produced by cuttings, budding, grafting, or layering.

INSPECTION FOR PLANT PESTS, like any other profession, has its own techniques. Inspectors learn what to expect in material coming from different parts of the world and how to look for pests. The most important function of inspection is not so much to find the expected as to find the unexpected. Interceptions have repeatedly revealed the occurrence of pests in countries in which they were not previously known to be present, and species of pests new to science are frequently encountered.

The inspector may be looking for specific pests, but he visualizes constantly what is normal for plant material of the kind he is handling. If his first inspection discloses something unusual, he makes a thorough investigation. With the normal in mind, he opens a bundle of perhaps 5o plants and spreads them out. Instead of examining each plant minutely, his eye may catch at a glance three or four plants on which he focuses his attention. He thus concentrates on material most likely to yield insect clues : He notices a tiny, clean-cut hole, such as might be made by a small needle. Lifting the bark with a knife blade, he may observe the work of a mining insect. A tiny grain, which the layman is likely to pass over as a grain of soil, he readily recognizes from its shape as the boring of an insect. The epidermis over a yellow spot on a leaf may cover the work of one of the many destructive species of leaf miner.

Going through a crate of bulbs, he develops a feel for them as he squeezes one bulb after another. He presses his thumb around a bulb at different places and may notice a slight give at one spot. On cutting into the bulb, which outwardly looks normal, he may find an insect larva.

A strand of silk on a plant may be the calling card of a leaf-feeding or other insect. A small knot on the root of a plant, which superficially looks like a little lump of soil, may be the home of an insect that has spun a cocoon camouflaged on the outside with tiny grains of soil.

An off-color plant is unfailingly investigated. On examining the under sides of pale-green leaves with a lens, the inspector may observe numerous tiny plant mites, but his interest does not cease with noting general color. A pinpoint of difference in color attracts him. Training his hand lens or the microscope on such a point, he may find it to be the egg of a plant mite. A tiny gray speck, the size of a flyspeck, may prove to be one of numerous species of sap-sucking scale insects.

Roughened bark at the base of buds and leaf scars is a place where some types of insects are likely to deposit their eggs. A scar on an otherwise smooth twig is likely to be evidence of the eggs of a leafhopper that were inserted under the bark. These, and others, are the clues an inspector uses for recognizing the presence of pests.

Character of growth may reflect the presence of insects as well as disease. A bunchy growth not normal to a plant may indicate the presence of insects that ate the terminal buds, with the result that lateral buds were forced into growth. A spindly, twiggy growth may be the symptom of a virus.

The temperature of the plant material is another factor. Living plants, even dormant woody material, have a feeling of coolness compared to dead material.

The inspector sometimes intercepts snails, lizards, and even tropical snakes with the plant material. While being photographed at the Hoboken inspection house, objects resembling beans, intercepted with orchid plants from South American jungles, were observed to move. Heat from the light used to photograph them completed the hatching of what proved to be snake eggs.

Among the plant pests that concern the inspector are wormlike animals eelworms or nematodes that are barely visible to the unaided eye. Some produce swellings on the roots of the plants they attack. The work of the common bulb nematode, Ditylenchus dipsaci, is recognized by cutting a cross section of the bulb. An infested bulb has concentric dark rings. The nematode commonly found in iris bulbs causes lengthwise yellow, brown, or nearly black streaks ( according to age of the infestation and the species of iris) or brownish specks or splotches at the tips of the bulb. The symptoms can be seen only when the dry, brittle outer skin, or tunic, of the bulb is removed by a blast of compressed air.

A nematode for which the inspector is especially alert is the golden nematode, a serious pest of potatoes and tomatoes. The female dries up and forms a cyst in which her eggs are contained. The eggs may remain alive in the soil for 10 years or more. That is a reason why quarantine regulations prohibit the entry of plants in soil the risk of introducing nematodes is great. Many species of nematodes can be identified by their cysts, which resemble round grains of soil or very small seeds. Occasionally plants or bulbs or plant litter in the bottom of a crate yield a bit of soil. If so, the inspector samples it for nematode cysts. He washes it and runs it through fine sieves. He puts what remains on a piece of absorbent paper to blot off the water and examines it under a microscope.

As important as keeping out plant pests is the work of excluding plant diseases. For instance, a number of plants may carry a virus disease of tobacco. Among them are primulas, of which only a small number are permitted entry. Arrangements must be made in advance of the importation so that provisions can be made at the inspection house for indexing. Indexing requires the sprouting of beans for use in tests. Juice of the primula to be tested is rubbed on a young bean leaf on which carborundum powder has been dusted. If virus is present, the bean sprouts develop visible spots or lesions in a few days.