Succulent Plant Pests

The loss of succulents due to pests can be quite frustrating to growers of these otherwise tough plants. In this blog, it should help to identify the pest that is attacking your succulents and determine the best type of treatment that suits you best. Happy hunting!

Signs of Ant Infestation:

Little “hills” of sand and small grit in sandy patches and alongside buildings.

Damage Done by Ants:

Ants seldom do damage to succulents, they are usually found in conjunction with sooty mold, scale and mealybugs. Ants have a symbiotic relationship with mealybugs and scale insects, the ants afford these types of insects with protection in exchange for honeydew (a sweet liquid excreted by aphids etc.).

The only damage usually seen done to succulent plants by ants is the building of their nests in the bottom of the pot and the damage being done is the consumption of roots.

Treatment of Ants:

If you have severe scale and mealybug infestations, it would then be a good idea to start killing ants as ants carry the sap-sucking insects from one plant to the other and in doing so they also spread sooty mold from one plant to the other.

Environmentally friendly:

• Leave some sugared water near the infected plants.  Treat infected plants as described in other pages.
• Sprinkle catnip or mint around the nests.
• Mix some chilis in with vinegar and spray the ants.

Aphids are small, delicate insects that are found in colonies on growth tips, flowers and leaves. Their color varies from yellow to black. Also called plant lice.

 Signs of Aphid Infestation:

Growth tips, leaves and flowers will be packed with aphids. Look for growth tips and leaves that are dying off as well as flowers that are stunted. aphids cause curly leaf syndrome, scroll down.

Damage Done by Aphids:

Aphids are sap feeders; they kill off growth tips and leaves and do damage to flowers. Certain species of Aphid’s saliva cause leaves to curl and twist together, curly leaf. Due to Aphids being sap feeders they may also transport other more serious plant diseases with them when they move to other plants. Aphids also secrete honeydew, a sweet substance that ants are fond of.

Treatment of Aphids:

Environmentally friendly:

• Make a solution of 5ml liquid detergent and 1l water, use the force of the spray to wash the Aphids off.
• Ladybugs are Aphids (Green Fly) s natural predator, introduce them into your greenhouse.

 Adult and immature insects are both small, flat elongated insects. Adult leaf bug insects are 3-4mm long and are straw colored.

 Signs of Infestation:

Leaf bugs are sap feeders, they suck sap on the lower surfaces of leaves which cause yellow spots and eventually cause the leaves to yellow and fall off. Severe leaf bug infestations may cause young shoots to die off causing bushy growth.

Leaf Bug Control:

Spray plants with oxydemeton methyl in September and November, vice versa if you are located in the Northern hemisphere. Spray infested plants when present.

One of the most common pests to occur in succulent, amateur and enthusiast alike, collections.  These pests can do severe damage to your plants if they are left unchecked.  Mealybugs can be quite difficult to control as they have a waxy coating over their bodies, and they tend to infest the harder to reach areas of plants.

Mealy bugs are soft-bodied, wingless insects up to 4mm in length, they are white to pink in color.  Adult mealy bugs are covered in white waxy threads and a waxy coating which makes them so difficult to eradicate.   They can be found on leaves (esp. the axil), stems and roots.
Mealy bugs have sucking mouthparts that they use to extract large amount of sap from the host plant.  These insects extract a large amount of sap in order to obtain enough proteins, the excess sap is excreted as honeydew.  The excreted honeydew attracts ants and sooty mould which inhibits the plants’ ability to manufacture food.

Signs Of Mealybug Infestation:

Non-infected plants can be infected from infected plats as mealy bugs can crawl from plant to plant.  Humans and animals may infect non-infected plants as they may be carried from one plant to the other.

Examine the foliage for individual bugs by looking at the upper and lower areas of the leaves, the axis (where the leaves join the stem), look between leaves especially tightly packed leaves and rosettes.  Severe infestations resemble patches of cotton all over the plant.

Damage Done by Mealybug:

Plants will seldom die of these pests due to heavy infestations being unsightly (you just can’t miss it).  Mealy bugs excrete a honeydew that attracts ants and possibly black sooty mold.  The ants and the sooty mold do not do much damage but rather makes the plant look unsightly. Mealy Bugs will kill off leaves and if left unchecked they will kill the plant. Mealy bugs also effect the development of flowers and stems (especially in succulents with fleshy stems).

Treatment of Mealybug:

Environmentally friendly alternatives to poison:

Biological control – Introduce Hypoaspis and/or Cryptolaemus (Australian Ladybird) to the infected plants.  Hypoaspis is a small mite that feeds on small insects, especially mealy bug.

Manual removal – You can pick the bugs off manually in plants that are not severely infested or use a strong jet of water (be careful not to damage plants).

Manual Removal – Use a 50/50 mix of water and methylated spirits to wipe away the bugs, the spirits should kill any remaining pests.

 Many species of nematodes are beneficial to the soil but there are nematode sap that attack plant roots, these are known as roor knot nematodes. Female nematodes are pear shaped while grubs and males look more worm-like. Nematodes are microscopic in size.

Signs of Infestation:

Infested plants will wilt quite easily in hot weather, plant become yellow. Knots on roots.

Damage done by Nematodes:

Nematodes prevent plants from getting all their vital nutrients from their roots, which will cause the plants to be stunted. Lesion nematodes cause dead spots around their feeding areas which allows other organisms to attack the roots which usually causes rot.

Succulent pelargoniums and Sarcocaulon species are susceptible to eelworm attacks.

Treatment of Nematodes:

Environmentally friendly:

Companion plants, like Marigolds, grown close to your plants and then dug into the ground chases the eelworms away. The smell of the Marigolds is apparently unbearable for the eelworms.

Red spider mites are between 0.5-0.7 mm in length, they are reddish brown in color, but some species may have different colors. Red spider mites thrive in hot dry conditions, they are often found on the underside of leaves.

Signs of Infestation:

Look at the lower surfaces of leaves as well as the yellowing of leaves. Red spider mites are sap feeders and plants that are infected often have leaves with fine yellow speckles on them. Another sign of infestation is the presence of fine web on the leaf.

In the succulent collection red spider mites infect plants with leaves that are pubescent (have fine hairs). Plants like Brachystelma and certain Pachypodium spp are susceptible to red spider mite.

Damage done by Red Spider Mite:

Red spider mites attack the leaves, their feeding habits will cause the leaves to go yellow and fall off.

Treatment of Red Spider Mite:

Environmentally Friendly Treatment:

• Soak twenty cigarette stubs in one liter of water for a week. Add 2.5ml liquid soap, which acts as a spreader/sticker, to the cigarette water. Apply to infected plants.
• Use water spray to remove mites.
• Oleum (Rape Oil) – 20ml/1l, spray onto affected areas. Oleum is a contact poison and will kill pests immediately.

 Red Scale is 1-2mm in diameter and oval in shape, they are reddish-brown in color and one can easily detect them on plants. Red scale is not fussy when it comes to attacking a plant, they will attack all parts of a plant, from the leaves to the stems.

Signs of Scale Insect Infestation:

Red Scale is easily detected.

Damage Done by Scale Insect:

Red scale has saliva that is toxic to the plant. The plant will drop its leaves prematurely and with severe infestations branches may die back.

Control of Scale Insect:

Environmentally Friendly:

• Apply a light mineral oil

Common garden snails can do a lot of damage to succulents in a short period of time, snails can devour mesembs overnight. Snails and slugs are known to attack aloes as well.

Treatment of Snails:

Environmentally friendly:

• Pick Snails off manually and crush them.
• Pour salt over them but be careful the salt may damage the succulent.
• Place a saucer of beer flush with the ground, apparently the snails are attracted to the beer and drown, this has never worked for me.

 Snout beetles or snout weevils are grey, dark brown to black in color. They are between 15mm-25mm in length. A distinctive feature of this pest is the elongated head that makes it appear to be a snout. The lesser Aloe weevils is particularly harmful to Aloes, 5mm-10mm in length, dark brown to black.

Plants attacked:

Aloes and bulbous plants.

Signs of Infestation by Snout Beetle:

Adults feed on aloe leaves causing circular lesions (3mm in diameter) with a transverse slit in the center and crown rot.

Damage Done by Snout Weevil:

Adult snout beetles will leave unsightly marks on the aloe leaves. The fat c shaped larvae are the culprits. Snout beetles lay their eggs at the base of the aloe leaves, the larvae bore into the stem just below the crown of the plant which may cause the entire plant to die.

Snout beetles are also known to attack bulbous plants.

Treatment of Snout Beetle:

Chemical:

• Adult snout beetle – gamma-BHC
• For larvae you will need to bore a 5mm hole at an oblique angle downwards into the aloe stem just below the crown. 5% oxydementon is then injected into the plants with a syringe.

 Adult whiteflies are small sap-feeding insects between 1-3mm in length. Their bodies and wings are covered in a white waxy powder; however, there are species that have a dark grey covering, they are known as blackflies. Eggs are laid on the underside of leaves, and the juvenile whiteflies resemble scale insects; they are also sap-feeders.

Signs of Whitefly Infestation:

• Yellowing of leaves.
• Leaves falling off prematurely.

Damage Done by Whiteflies:

Severe infestations of whitefly will cause leaves to wilt, turn yellow, and fall off prematurely.

Plants Attacked by Whitefly:

• Mesembs
• Leafy succulents – especially caudiciforms
• Beans
• Tomatoes

Treatment of Whiteflies:

Environmentally friendly:

• For small infestations, remove flies by hand.
• Make a loop of bright yellow electrical/insulation tape into a loop, sticky side on the outside, place it near to the infected plant.  The white flies are attracted to the yellow color and will get stuck onto the sticky tape.

 The larvae of moths and butterflies.

Signs of Worm Infestation:

Stripped leaves and droppings.

Damage Done by Worms:

Worms will strip away leaves overnight and some attack the roots.

Control of Worms:

Environmentally friendly:

• Pick worms off manually.

#succulents #mealybugs #pestsonsucculents
Hopefully, you were not grossed out and learned something!