Stem and bulb nematode

Ditylenchus dipsaci

Stem and bulb nematode is a roundwormthat lives in soil and plant tissues, primarily infectingonionandgarlic plants. The feeding and movement of the nematode causes large cavities in the infected tissue. Infestation is encouraged by wet conditions and mild temperatures (15-20 °C), and is adversely affected by dry conditions and temperatures below 10 °C and above 22 °C.

Potato rot nematode

Ditylenchus destructor

Potato rot nematode is a tiny roundworm that can cause significant damage to the underground parts (roots, tubers, bulbs) of host crops. Such crops include potatoes, sugar beets, carrots and garlic. It can reduce harvest yields of host crops and cause additional damage during storage. In South Africa, nematodes are often referred to as eel- or roundworms because they resemble the common earthworm, but these parasites belong to a different grouping or phylum.

Heartworm nematode

Dirofilaria immitis

The heartworm nematode is a parasitic roundworm that is spread through the bites of mosquitoes. It causes heartworm disease in animals such asdogs, cats and, rarely, humans. Occasionally, adult heartworms migrate to the right side of theheart and even the great veins in heavy infections. Heartworm infectionmay result in serious disease for the host, with death typically the result of congestive heart failure.

Triploid grass carp

Ctenopharyngodon idella

Thegrass carpis anherbivorous,freshwaterfishspecies. It was introduced into South Africa from Malaysia and Germany between the years of 1967 and 1975. In large numbers, it can remove all aquatic vegetation from a body of water. If this happens valuable habitat for fish is lost which can cause fish population imbalances.

Grass carp

Ctenopharyngodon idella

Thegrass carpis anherbivorous,freshwaterfishspecies with an elongated, chubby, torpedo-shaped body.This species occurs in lakes, ponds, pools and the backwaters of large rivers, preferring large, slow-flowing or standing water bodies with vegetation.


Crotalus species

Crotalusis agenusofvenomouspit vipersnaturally occurring in theAmericas,from southernCanadato northernArgentina. Therattlesnakescurrently found in South Africa include the sidewinder (Crotalus cerastes), which is a desert ambush predator. Members of this genus range in size from 50 - 60cm to over 150cm. Most forms are easily recognised by the characteristic rattle on the end of their tails, although a few island populations are exceptions to this rule.

Japanese oyster

Crassostrea gigas

The Japanese oyster is native to the Pacific coast of Asia. It has been introduced to many parts of the world for aquacultural and ecological purposes. Introducing the species in vast quantities throughout the world has had a negative effect,and it isnow considered an invasive species.

Banana root borer

Cosmopolites sordidus

The banana root borer is a major pest of the banana plant and infests all types of bananas. The insect originated in Southeast Asia and has spread to all the important banana and plantain plantations in the world. It is not usually a pest in its area of origin.

Feral pigeon

Columba livia domestica

The feral pigeon is a descendant of the domestic homing pigeons introduced to South Africa from Europe in the 1800s. Several traits have allowed feral flocks to increase in numbers and dominate the urban landscape due to the availability of food, fresh water and secure breeding sites. They carry a number of potential diseases such assalmonella, tuberculosis and ornithosis.

Sea vase

Ciona intestinalis

Sea vase is highly competitive species that is a major pest of shellfish aquaculture production. Indigenous to the northern Atlantic Ocean, it has been recorded as an invader of harbours in both temperate and tropical climates. In South Africa, it has been recorded in harbours ranging from Saldanha Bay to Durban.