At present there is little evidence from Namibia that pests are important when picking Ombidi plants for spinach. A few pest species have noticed occasionally but they do not yet seem to cause much damage.

• Records from other countries indicate that the important species Ombidi (Cleome gynandra) may suffer from pest attacks by species that are also present in areas of Namibia, e.g. Bagrada bugs (Chweya and Mnzava, 1997). If ombidi species are to be cultivated as intensive mono crops in future, one would expect pest attacks to become more important.

• Ombidi plants are the first plants available in large numbers at the very start of the rains. Field crops are sown at that time and their plants are not available to most pests until a few weeks later. Ombidi plants may therefore serve as a refuge for pests that can survive and multiply until they later on spread to the cultivated crops on the field. This may be of importance to pests such as Red Spider Mites and Blister beetles in cultivated crops.

• Ombidi species are found as weeds in most Namibian fields and gardens. This makes it difficult or very risky to control pests in these crops with chemicals. When a cultivated crop is sprayed with a chemical, the Ombidi plants are sprayed as well. They will be poisonous for some time and should not be picked for consumption.

Namibian pest records

Caterpillars. A mixed Ombidi sample (ombidi and ekwakwa) which was collected at Odibo in Ohangwena region during early 1998 contained many caterpillars of an unknown moth species. The farmer had to sort all the tiny plants and discard the caterpillars before preparing the food. The caterpillars were reared and adult moths hatched a week later.

Spider mites.
During December 1996, red spider mites were observed in large numbers on ekwakwa (Amaranthus spp.) in a watermelon garden near Tsumeb town, Oshikoto region. It is a reminder that red spider mite may use ekwakwa as a host plant before spreading into the vegetable crops that are often grown later in the year.
 

Leaf miners.  Symptoms of a leaf miner were noticed on ombidi plants (Cleome gynandra) in a garden in Oshakati town (1998). The miners made small circular spots in the leaves, the spots were pale green and quite conspicuous on the plant. The leaf miner was not  identified and the importance of this leaf miner is unknown. Leaf miner symptoms on Ombidi leaf

Blister beetles. Flowers of especially ombidi (Cleome gynandra) are conspicuous among the weeds in Namibian fields. They attract a large number of blister beetles and other beetles that feed on the flowers. It is uncertain whether these beetles actually do any real damage to the flowers or the seed setting. When ombidi species flower, they are usually too old to be used as spinach anyway, so a possible damage could only be in reduction of seeds for next season. Mylabris tincta on Ombidi flowers

CMR-beetle.  Plants of ombudje (Sesbania pachycarpa) may serve as a reservoir for blister beetles such as the CMR-beetle (Mylabris oculata) which is very common in northern Namibia. Ombudje plants flower profusely with yellow flowers after the rainy season (April-May) and keep flowering long into the winter time as one of the few flowering plants at that time. Mylabris oculata on mahangu head

Seed pests. 
During the seed collection of five common Ombidi species (1994), tiny pests were found in a few of the seed samples. The pests were extremely small, smaller than the size of seeds. They had not been noticed before as it is not common to pick Ombidi seeds and store them. In the small-seeded ombidi (Cleome gynandra) there was a small beetle, while in the larger seeded ombudje (Sesbania pachycarpa)  there was another beetle. Seed samples and pests were lost in transport, so no identification was possible.

Spots on omundjulu and engamundjulu
Leaves of Omundjulu and especially  engamundjulu are often covered with numerous white or creamy spots that are a few millimetres wide. It is still unknown whether this is caused by exudates from the thick leaves or by a fungal disease.