Ladybeetles (Ladybugs or Ladybirds) at a glance
|Occupation:||Predator or Pest|
|Value to Gardener:||3/5 – Pest Controller (some are pests!)|
|Danger to Humans:||1/5 – Harmless|
|Availability:||5/5 – They’ll arrive or you can buy some|
Ladybugs, ladybirds or ladybeetles; these insects are firm favourites amongst gardeners and non-gardeners alike with the classical image of a red-and-black-spotted beetle coming to mind. Little do most people realise that, yes, most ladybirds are beneficial and gobble up aphids, but many are pests too, devastating crops overnight!
Ladybeetles have been unfortunately miss-named by the more popular term ‘ladybug’, since they aren’t true bugs (those belonging to the Hemiptera family are bugs; where half of the wing is membranous and the other half is hardened).
Ladybeetles are beetles belonging to the Coleoptera order of insects and have forewings that are completely hardened to elytra. The forewings cover the hind wings, which are fully membranous and used for flight.
Ladybeetles belong to the Coccinellidae family of beetles. They have many different combinations of black, yellow, orange, red colours arranged in a myriad of stripes and spots or are otherwise pattern-less.
Ladybeetles are where their prey items or food plant is. This means that the beneficial ladybeetles fly in and breed on plants with prey items, whereas pest-species invade agriculturally-important crop stands.
Most adult ladybeetles and larvae are carnivorous and will munch through armies of aphids, mealy bugs, thrips, scale and similar soft-bodied vegetable pests. Some ladybeetles are generalists, feeding on a wide range of pest insects, whereas other might specialise in a few, see table below.
Beneficial ladybeetles, their names and pests they specialise in destroying:
|Common Name||Scientific Name||Pest eaten|
|Black two-spot ladybeetle||Chilocorus distigma||Red scale of citrus|
|Black-ringed ladybeetle||Oenopia cinctella||Psyllids, leaf beetle eggs & larvae, black and green aphids|
|Humbug ladybeetle||Micraspis striata||Small insects (thrips)|
|Spotted Amber ladybeetle||Hippodamia variegata||Aphid specialist|
|Chequered ladybeetle||Harmonia vigintiduomaculata||Soft bodied pests (aphids, mealy bugs, scale)|
|Lunate ladybeetle||Cheilomenes lunata||Aphids|
|Black mealy bug predator||Exochomus flavipes||Aphids, mealy bugs, soft scale, cochineal insects|
The Lunate and Black Mealy Bug Predator ladybeetles are dispersed across South Africa, which means that when you garden is under attack these super-beetles will come to the rescue. The Black Two-Spot and Humbug ladybeetles occurs Northern and Eastern parts of South Africa, whereas the Spotted Amber ladybeetle also occurs along the coast. The Chequered ladybeetle is only found along the eastern coast line and the Black-ringed ladybeetle is found in the Cape regions.
There is one big consideration you should be aware of when relying on your ladybeetles for pest control: Ladybeetles will only be present when a heavy infestation of pest species are available (thick layers of pests on several plants). This means no pesticide use, organic or otherwise, so that pest populations can reach large enough numbers to attract ladybeetles. Once the ladybeetles arrive they will make short work of the pests on the plants. So the trade-off would be resisting the urge to wipe out the aphids until the ladybeetles are recruited. I am not sure about the exact amount of aphids our South African species can gobble in a day, but numbers range from 50-300!
I get a lot of ladies in my garden every year. Yes, I do not spray pests anymore, organic or otherwise. It started mostly out of laziness, but then I had all these wonderful ladybeetles arriving to assist with my massive aphid infestation. The major infested crop each year is the Florence fennel and it usually maintains the ladybeetle headquarters. Other infested plants included the peach, which is subsequently cleared of aphids by the beetles, and the potatoes, mainly at their leaf tops until they finished cropping and die. One year I removed the fennel, (as it was bolting not ‘bulbing’ in the hot sun, hence all the aphids) after a huge rain storm washed away most of the aphids, all the ladybeetles left for better pickings. Ever since I have left the fennel as a permanent feature in the garden. Here are some photos of the ladybeetles (larvae, pupae and adults), which you will likely find in Gauteng, Johannesburg, Sandton and the surrounding areas (Roodepoort, West Rand…).
I did mention that the Black-ringed ladybeetle is a Cape inhabitant, but I think it might have been transported to Gauteng, because I have whole swarms of them each year, including several morphological variants (morpho. var.). Ladybeetles and their variants are hard to ID, since spots and colours can change drastically! The community at Project Noah helped me out with IDs, so here are the ladybeetles morpho-variants adults as well as some pupae and larval stages:
Now we get to discuss some of the herbivorous ladybeetles. These ladybeetles lay their eggs on the undersides of leaves, both larvae and adults are herbivorous, quickly skeletonising leaves. Most plants affected are the Cucurbits (squash, pumpkin, watermelon, cucumber) and Solanaceae crops (peppers, tomatoes, potatoes, eggplant, nightshade, Cape gooseberry).
|Common Name||Scientific Name||Plants eaten|
|Cucurbit ladybeetle||Henosepilachna bifasciata||Cucurbits (pumpkin, watermelon, cucumber) and potato|
|Nightshade ladybeetle||Epilachna paykulli||Solanaceae family (potato, tomato)|
|Potato ladybeetle||Epilachna dregei||Potato, tomato, peppers, sometimes cucurbits|
The Cucurbit and Nightshade ladybeetles are widespread throughout South Africa, so there is no escaping them! The Nightshade ladybeetle is restricted to the Northern and Eastern parts of South Africa.
I had a massive infestation of Potato ladybeetles on the potatoes growing in the old pumpkin patch once. The best way to deal with them is to pick them off by hand (into a plastic bag) and stomp on them (instant death). Any chemical pesticide that could wipe them out will also harm other ‘higher’ beneficial insects, such as spiders, bees, beetles and mantids. Unfortunately, I don’t have an organic alternative recipe, which would likely also harm other beneficials, so the only option is physical removal. Be careful when picking them off as they squirt a yellow liquid onto your hand that is smelly (a defence mechanism, known as reflex bleeding, which is unpleasant for predators to eat). Otherwise if you could get some spider and mantids into the patch, they’ll likely lighten the infestation load by eating a few.
I was convinced that I had taken pictures of the Potato Ladybeetle larvae, but clearly I was mistaken. They are about half the size of the other larvae, very bright orange and they are full of spikes. Whenever I see one again, I’ll take a pic and post it here…
Ladybeetle – SOS
Globally we have a problem with our ladybeetles, much as with our amphibians, due to habitat destruction and the introduction of invasive species. The most prominent invasive species are:
|Common Name||Scientific Name||Problem status|
|Multi-coloured Asian ladybeetles (MALB) or Harlequin ladybeetle or Halloween ladybeetle||Harmonia axyridis||World-wide invasion problem. In spring they eat aphids, in winter they feed on fruits leading to spoilage. MALB are sometimes crushed with grapes during wine-making and taint the wine with their reflex bleeding alkaloids.|
|Mexican Bean Beetle||Epilachna verivestis||Especially problematic in the United States. Herbivore that destroys several legume crops, such as beans, alfalfa, peanut, clover and others (okra, squash , eggplant).|
It seems that exotic ladybeetles have a greater survival capacity than native ones, partly due to native beetle egg predation being less than exotics ladybeetles. This means that exotic ladybeetles are under less stress, produce more larvae and have greater overall populations, which out-compete native ladybeetles (Ref 1). Another possibility is that the invasive beetles carry disease-causing organisms unfamiliar to native beetles, which end up becoming infected and die, Ref 2 (much like when Smallpox was brought to America by European explorers and devastated the native Indian populations).
Several movements have been established to conserve and document native ladybeetles, such as The Lost Ladybug Project (North America) which aims to protect native ladybeetles. They also have a ladybeetle identification tool and links to additional projects with the same aim but for other animals. You can also make contributions of your ladybeetle spottings on Project Noah, and The Lost Ladybug Project is also there as Mission 34021.
Ladybeetles last thoughts…
Ladybeetles are definitely great biological control agents, but you have to wait until pest species multiply to high enough densities in order to have ladybeetles coming into your garden. Additionally, herbivorous species may cause confusion, especially amongst the larvae and pupae spotted in the garden. We all need to do our bit to help preserve our native species, such as the removal of invasive species, reduced pesticide use and help to document native species we see in our gardens.
Ref 1: Smith C. A. and M. M., Gardiner. 2013.Biodiversity Loss following the Introduction of Exotic Competitors: DoesIntraguild Predation Explain the Decline of Native Lady Beetles? PLoS ONE 8 (12):e84448.