Like all plants, unfortunately there are a whole host of nasty pests and diseases just waiting to feast on your hard work. Thankfully here at Chillilicious we've put together a guide to quickly help you diagnose and treat any issues you may face when growing chilli plants.
In general, there are two types of factors that can bring devastation to your beloved plants - living and non-living agents. Living agents include insects, bacteria, fungi and viruses. Non-living agents include poor temperature, excess moisture, poor light, insufficient nutrients, poor soil PH and air pollutants.
These little devils can turn a row of your prize seedlings into useless stumps overnight! Thankfully most slugs and snails leave you a lovely trail of slime to help diagnose the issue. Slugs are hermaphrodites (they can mate with themselves) and can produce dozens of eggs several times a year. The egg clusters look like piles of whitish jelly and hatch anywhere from 10 to 24 days after laying. Remove and dispose of any clusters you find. For the adults, regular slug hunts are the best method of control. You will often find them sleeping during the daytime under the chilli pots. For prize plants you can use copper tape/matting around the pot. Slug pellets are an option if you are having a particularly hard time but these are dangerous to other animals who eat them.
Aphids A chilli grower's absolute nightmare, these pests can be hard to spot until the infestation is out of control. Generally green in colour although you will also find them in pink. They are particularly attracted to young shoots, sucking the plants dry of sap which causes shoots and leaves to become distorted. Plants grown indoors away from natural predators are particularly vulnerable. If you keep your plants in a greenhouse it is easy to use the method we implement to control aphids. We buy in ladybirds, ladybird larvae and a predator fly called aphidius. By letting these loose in the polytunnels they munch their way through any infestations and are the only method of eradicating aphids that we have found to be foolproof. The predators will start breeding in the greenhouse/polytunnel and as long as there is a food source they won't leave. Another effective method of aphid control is to rub off the pests manually with a diluted soap and water mixture, about one teaspoon of fairy liquid to 2 litres of water. Do not dump the whole mixture over the entire plant - you may kill it. If you have a serious infestation and you are growing indoors, your only option may be to use chemical warfare. There are several varieties available however you should manually remove the aphids as well as using chemicals. Read instructions carefully, do not over use and take special note of how the particular chemical you are using affects the consumability of the pods.
Caterpillars Although not a common pest you may occasionally find them munching through your seedlings. Look out for serious leaf damage, rolled up leaves (the caterpillars are inside), and dark eggs approx 1-2mm in diameter on underside of leaves. Manually remove adults and eggs.
Flea Beetles About 2mm long, shiny in appearance with enlarged hind legs which enable them to jump. Adult flea beetles feed on the undersides of young leaves leaving small pits or irregular shaped holes. Larvae live primarily in the soil and feed on roots although cause little damage. The best method of avoiding this pest is to germinate and develop your seedlings quickly so they grow through the vulnerable stage and can handle the attacks. Flea Beetles also don't like getting wet, while they are feeding in the height of the day give your plants a lunchtime shower. That should deter them, you can also remove them manually.
Pepper Maggots Whitish yellow, pointed at the head and about 0.5 inches when fully grown. The maggots feed on the core inside the chilli pods which causes the peppers to turn red prematurely and rot from the inside out. Check your pods for small entry holes and destroy infected chillies. Rotting pods will attract other pests if left on the plant.
Nematodes (Root Knot) Nematodes are tiny transparent roundworms that live in the soil and feed on roots. Root damage reduces the plant's ability to take up water and vital nutrients. Symptoms vary with infestation severity but may include wilting, non-productive plants and development of characteristic knots on the roots which can vary in size from a pinhead to a pea. The problem can be particularly severe in sandy soils. Crop rotation and adding organic matter to soil can help reduce the impact of nematodes. If using pots and infection is severe completely repot the plant trying to remove as much old soil as possible. Certain chillies are more susceptible to nematode attack, in the same light there are chilli varieties that are particularly resistant.
Spider Mites Can be a serious problem particularly during periods of hot, dry weather. They feed on the underside of the leaves and to the naked eye look like tiny moving red dots. When infestation is high the leaves will have webs on them. If uncontrolled these mites will kill the plant. Infected leaves often turn downwards and leaves have a speckled appearance. A simple technique to identifying spider mite is to tap a possibly infected leaf over a white piece of paper, wait for a few seconds and look for movement. These nasty little pests breed in hot, dry places. If you can increase the humidity around the plant you will decrease the mite reproduction rate. For a houseplant you could spray with water to dampen infected leaves, alternatively you could also place the plant pot in a cooler and more humid room (like a bathroom), that could help get rid of the infestation. There are also various chemical sprays you can use, read the instructions carefully and take note of how they affect your ability to consume the chilli pods.
Thrips Slender, very small and may appear white, yellow, brown or black. Affected leaves are often distorted and curl upward. The lower surface of the leaves can develop a silvery sheen that later turns bronze. Damage on the pods appears as brown or silver. You can use a chemical to control thrips, however manual removal of affected leaves and pods do the job just as well.
Whitefly Tiny insects about 1.5mm long with broad wings that fly from plant to plant when disturbed. They suck plant juices from the leaves, causing them to shrivel, turn yellow and drop off. Whiteflies also secrete honeydew which can cause foliage to become sticky and coated with black sooty mould. Whitefly control is difficult since only the last (flying) stage of the lifecycle is vulnerable to chemical spraying. They have very fast lifecycles and therfore require spraying quite often which can also affect your plant. Using a diluted soap mixture (see Aphids) and manually remove the whitefly as well as removing infected leaves is the best method, although it can take many weeks to eradicate the infestation.
Bacterial & Fungal Diseases
Anthracnose Caused by the fungi Colletotrichum piperatum and C.capsisi and is promoted by warm temperatures, high moisture and poor air circulation between plants. Athough the disease does not affect pod growth it can seriously damage the pods themselves. Symptoms appear in both ripe and un-ripe pods and are characterised by sunken, circular spots that can grow up to 1 inch in diameter. In moist conditions, pink or yellow spore masses may appear. Crop rotation and the use of disease-free seed controls this fungus. Remove affected pods, if disorder is severe a fungicide may be needed.
Bacterial Leaf Spot Caused by the seed borne bacterium Xanthomonas campestris pv. Vesicatoria which also causes bacterial spot in tomatoes. Moist conditions encourage disease development however the principle source is infected seeds. The disease first appears as small water sacked areas that enlarge up to a quarter of an inch in diameter. The disease spots have black centres and yellow halos. The spots are depressed on the upper leaf surface whereas on the lower surface the spots are raised and scab like. Severely spotted leaves will eventually turn yellow and drop off leaving pods susceptible to sunscald. To avoid this condition buy disease-free seeds from a reputable grower only. The use of copper based fungicides can have some success in controlling the issue although may cause growth issues.
Bacterial Soft Rot Caused by the bacterium Erwina carotovora pv. Carotovora and affects chilli pods. The internal tissue softens before eventually turning into a watery mass with a foul smell. This problem is worse in wet conditions because the bacteria are splashed from the ground up onto the fruit. It can also be spread by insects. Keeping plants off the ground and controlling insects can help help with avoiding this disorder. Remove affected pods immediately.
Bacterial Wilt Caused by the bacterium Pseudomonas solanacearum. The first symptoms start with the wilting of the leaves. After a few days the entire plant will wilt with no leaf yellowing. Test for this condition by cutting the roots and lower stems, then look for milky-white streams when they are suspended in water. There is not much that can be done for a plant with this condition, always buying seeds from reputable growers can help avoid this condition.
Cercospora Leaf Spot (Frog Eye) Caused by fungi Cercospora capsici and is worst under extended warm, wet conditions. The disease is characterised by small brown circular leaf lesions that have a watery appearance. Excessive leaf drop may occur in large infestations. Good airflow around the plants will minimise the problem. If the problem is severe you may wish to consider a fungicide - read insructions carefully and take note of how using this chemical affects the edibility of the pods.
Damping-off Caused by poor seed quality, improper planting depth, high salt concentrations, wet seed beds or severe nutrient difficiencies. Seedlings fail to emerge (pre-emergence damping-off), small seedling collapse (post-emergence damping-off) or seedlings are stunted (root rot or collar rot). Poorly drained soil is often a major cause of this condition, good ventilation around the plants helps. A copper based fungicide or chamomile tea can reduce further damping-off.
Grey Mould A relatively common problem with chillies, it is caused by the fungus Botrytis cinerea. Fun fact: 'cinerea' in species names means 'ashy' and typically refers to grab, ashy, or sooty-looking features.Symptoms include a sudden collapse of succulent tissues, such as young leaves, stems and flowers. Grey powdery spore masses occur on the surface of dead plant matter. This condition is worsened by high humidity, ensure your plants have good air circulation. Remove affected areas of the plant immediately. You may wish to consider a fungicide if severe.
Phytophthora Blight (Chilli Wilt) Caused by a water-borne fungus called Phytophthora capsici and is generally found in wet waterlogged areas. The fungus invades all plant parts causing the syndromes leaf blight, fruit rot and root rot. Plants suffering from this conditions often wilt and die very quickly. Once the fungus enter the roots the plant is beyond saving unfortunately due to root rot. The condition may also affect a section of the plant rather than the plant as a whole. This section is often bordered with white mould - remove immediately. Avoid excess watering of plants and try to give your soil good drainage. A fungicide can be used on the leaf blight and fruit rot symptoms however root rot is usually terminal.
Powdery Mildew Caused by the fungus Leveillula taurica and primarily affects the leaves of chilli plants in warm wet conditions. This disease generally affects older leaves and symptoms include patchy white, powdery growth that can enlarge to cover the entire lower leaf surface. Diseased leaves eventually drop off leaving pods susceptible to sunscald. This condition generally requires a fungicide, affected areas should be removed manually if possible.
Verticillium Wilt Caused by the fungus Verticillium dahliae, it is a soil-borne fungi which can infect the chilli plant at any growth stage. Cool air and low soil temperatures can worsen the condition. Plants may show yellowing of leaves and stunted growth. As the disease progresses the plants can shed leaves and may finally die. If the stem is cut, a brown discolouration may be visible. Crop rotation is the only control currently.
White Mould Caused by the fungus Sclerotinia sclerotiorum. It causes blighting or rotting of any above or below ground plant parts. At first the affected area of the plant has a dark green, greasy or water-logged appearance. On the stems, the lesion may be brown to grey in colour. Controls include well drained soil, proper plant spacing, crop rotation and careful removal of infected areas/plants.
Pepper Mosaic & Pepper Mottle Virus (PeMV) Caused by infected aphids and other insects that have come into contact with the plant. Symptoms include stunted growth, distorted fruit, and chilli pod yield reduction. Best avoided with good aphid control, remove infected plants although control is often difficult.
Tobacco Etch Virus (TEV) Caused when infected aphids and other insects come into direct contact with the plant. Symptoms include dark green leaf veins, leaf distortion and stunted growth. Tobacco chilli plants are particularly susceptible to this disease and will often wilt and die. Best avoided with good aphid control, remove infected plants and planting known resistant varieties. Control can be difficult.
Tobacco Mosaic Virus (TMV) Highly infectious and persistent disease that is carried by tobacco in cigarettes. Spread by touching plants after handling tobacco or smoking. Symptoms include curling leaves, spotted or mottled fruit, stunted growth and excessive leaf drop. Smokers should always disinfect hands (milk kills TMV) thoroughly before touching chilli plants. Remove infected plants although control can be very difficult.
Nutrient/Mineral Deficiency We've created a diagram that should help you identify any possible nutrient or mineral deficiencies that your plant may be suffering of. We use Chilli Focus to feed our chilli plants however depending on your deficiency there are a range of other fertilisers you can also use.