THE RADISH: The most important pests and diseases

In the previous article we saw some tricks on how we could grow radish, but we left the issue of pests and diseases pending. Therefore, today we will try to discover which are those bugs and microorganisms that most affect this vegetable.

1. Radish pests

Aphids

Aphids, as we have seen in other articles, are one of the most common pests in orchards and gardens. They are small in size (1-3 mm in length) and can present different colors depending on the species to which they belong. They attack young shoots of crops with high sugar content. The larvae cause damage by making galleries in the leaves of the plants.

As for adults, they feed by sucking the sap from leaves, buds and young shoots using the stylet of their mouthparts. In addition, they excrete a sticky, sugary liquid called molasses that attracts ants. They favor the appearance of a fungus known as bold and can also transmit viruses from one plant to another.

In the following image you can see an example of this plague:

Some control methods that you can use are based on: Eliminating weeds, good substrate preparation, color traps, pruning or natural enemies such as ladybugs, lacewings, earwigs or wasps.

White fly

Whiteflies are generally located on the underside of leaves . They like humidity and high temperatures, which is why it is a frequent pest in spring and summer (very dangerous in greenhouses!).

The main damages they cause to crops are:

• Extraction of sap from the plant.
• Mechanical damage
• They produce molasses.
• Some species are disease vectors.

The best method of control is prevention . Therefore, it is important that you check the underside of the leaves from time to time in order to act as soon as possible. In addition, there are various methods of whitefly control such  as chromatic traps, natural predators, wormwood infusion, garlic, etc.

Cabbage caterpillar (Pieris brassicae)

The cabbage butterfly , Pieris brassicae , is a lepidopteran of about 5 cm or 6 cm, white and with black spots. It usually feeds on the cruciferous family (Brassicaceae), that is, cabbages, cauliflowers, radishes, Brussels sprouts, etc.

The eggs of this butterfly hatch in approximately 8-10 days and give rise to small gray larvae. These larvae are very voracious and will begin to pierce the leaves of radishes with their chewing mouthparts. They can become a very important pest in this family of plants! Once they pass their larval phase, they will pupate to become butterflies.

Its adult form is characterized by having two points on the wings, like those seen in the image.

I leave you the link to an article where you can read some remedies to kill the cabbage caterpillar .

Black donut

The scientific name for this lepidopteran is Spodoptera littoralis . It is a caterpillar that feeds mainly on the inner leaves. Throughout the day they hide and at night is when they feed. Usually the laying is done in the aerial part of the plant, on the underside of the leaves. When they turn into butterflies they no longer do any harm.

For its control it is recommended:

• Set pheromone traps.
• Monitor the first stages of crop development, since this is the time when they are most susceptible.

Snails and slugs

Snails and slugs are a type of herbivorous mollusk that are very fond of moisture. For this reason, they usually come out when the environment is warm and humid (when it has just rained, at night, after watering, …). If we let them roam freely in the garden, they can affect the leaves and fruits of almost all plants. The problem is usually not very serious unless there are too many.

The best method to remove them is manually, but there are other methods to remove slugs and snails that you can find at the link.

2. Diseases

Mildew: leaves with brown spots

Another fungus that affects radishes is Mildew. It produces greasy-looking spots of different shades on the leaves, which later turn brown and wilt.

I have not found any photo of how the mildew affects the radish leaves but I leave you a picture of how it affects the tomato leaves.

3. PATHOPHYSIOLOGY IN RADISH

• HOLLOWED:  Sometimes, if we allow the radish to ripen too much, what we know as «hollowed out» can be produced.
• SPICY FLAVOR: The spicy flavor will be greater if the radish has been overheated or harvested too early.
• HARD TEXTURE:  In soils that are too light or with a water deficit