Repotting of plants is necessary in plantings where growth is allowed. Containers need to be removed from the planter and from the plant, the next larger size selected, and the excess space filled with growing medium. If roots are matted, they should be loosened before repotting. If they have started to grow around themselves, the large and excess roots should be pruned away. The pot should not be filled to the rim with the growing medium. An inch of unfilled space below the pot rim will give water room to flow into the container.

Insects and Diseases

Insects and diseases are not as common to interior plantings as to exte­rior ones, but they do occur. Insect problems are more common than diseases.

The initial pest presence may be introduced by the plants them­selves as they arrive from the grower. Insects or pathogenic inoculum may be present in the foliage, roots, soil, or containers. All should be checked carefully on arrival, at an area away from the installation site. The same careful check should be made each time replacement plants arrive. Obviously, a reputable grower is the first defense against pests.

The most common pest problems of interior foliage plants are:

• aphids

• mealybugs

• spider mites

• white flies

• scale

• thrips

• nematodes

• root mealybugs

• root rots

• leaf spots

• anthracnose

• mildews

• blights

These pests and others are not uncontrollable when modern pesti­cides and methods of application can be used against them. However, the interior location and the presence of people make the use of sprays, dusts, and fumigants difficult. Whenever there is the possibility of people making contact with the pesticide, it is dangerous to use. Even furnishings and carpeting can be damaged by many of the corrosive or oil-based chemicals. Where practical, plants can be wrapped in loose plastic bags and sprayed within the bag. This helps reduce the drift and the danger to people and furnishings.

Control measures are restricted to:

• chemical pesticides approved for application indoors

• removal of infected or infested plant parts

• washing away of insects and inoculum from plant foliage

• replacement of plants with healthy new ones