plankton. n. 1. (Biology) the organisms inhabiting the surface layer of a sea or lake, consisting of small drifting plants and animals, such as diatoms.Compare nekton. [C19: via German from Greek planktos wandering, from plazesthai to roam].lankton is a primary food source for many animals, and consists of bacteria, protozoans, certain algae, cnidarians, tiny crustaceans such as copepods, and many other organisms. Microscopic aquatic organisms that float near the surface of water.
Descriptions of Common Tomato Diseases. 1  Anthracnose - small, circular, slightly sunken spots... 2  Bacterial Canker - wilting, browning plants and bird's-eye fruit spots. 3  Bacterial Spot - small, dark, slightly raised dots on fruit... 4  Bacteria Wilt - entire plant dies rapidly after browning... 5  Blossom End Rot - spot on bottom of fruit turns black and...
Problems on tomato leaves ... Problems on tomato stems ... Other tomato problems ... Tomato diseases: how to identify, control, and prevent them ... Blossom end rot: how to identify, control, and prevent it ... Tomato pests: how to identify, control, and prevent them 1  ... Plant healthy, disease-free plants. 2  Stake plants to allow good air circulation to fruit. 3  Water at the base of plants. 4  Overhead water spreads disease easily. 5  Water in the morning or midday to minimize the amount of time fruit is wet.