Gardeners Tips

Leaf miners are the larvae of moths, beetles, maggots, flies or caterpillars that have hatched between the upper and lower epidermis of a leaf. They then burrow there way out eating part of the leaf and leaving a trail.

Common Types from 524 Leaf Miners

• Chrysanthemum leaf miner ‘Phytomyza chrysanthemi’ also known as the Margurite fly.
• Privet leaf miner ‘Gracilaria cuculipennella’
• Palm leaf miner ‘Homaledra sabelella’
• Other favourite indoor targets include Ficus species and African Violets.
• A few mining insects use other parts of a plant, such as the surface of a fruit.
• The horse chestnut leaf miner ‘Cameraria ohridella’

Damage and Control

• Deterioration of plants leaf by leaf results from the tunneling or mining activity.
• Some damage is linear some is serpentine.
• Blotches and circular ruptures may occur where the surface has been eaten away.
• Sprays are largely ineffective as the insect is protected under the surface of the leaf.
• Systemic insecticide is the only cure. Insecticides recommended for leaf miner control on farm crops include carbaryl, chlorfenvinphos, diazinon, dimethoate and trichlorphon.
• Infected leaves should be pruned off and destroyed.
• Farmers may reduce or prevent problems by planting trap or distraction crops near the plants to be protected

Sources Creative Commons
Top; by Martin LaBar, on Flickr’ leaf miners, insects that, generally as larvae, burrow between the upper and lower epidermis of leaves. An interesting ecological niche!’
Lower; leaf miners by tonrulkens, on Flickr

Read British Leaf Miners

A rest

Keep Plants and Pots Tidy to Prevent Disease

• Potential breeding places can be eliminated by sprucing up your plants,
• Deteriorating leaves and faded or dead blooms should be removed.
• Dead leaves and debris should be picked off the surface of the soil.
• Dust off any obstructions that can block the pores of the leaves. Some plants benefit from a damp sponge on the leaves.
• In the case of sick and infested plants disinfect/steralise saucers and containers.

Give Plants What They Need

• A rest may be all a plant needs if it been performing flowering miracles through summer
• Provide the right conditions to suit the type of plant.
• Do not over water or leave standing in water.
• Provide the right sort of soil for the plant. Special composts are now pre-formulated for Orchids, Cactus, acid lovers, Bonsai etc.
• Keep temperatures at a consistent and appropriate level.
• Give plants adequate light and avoid sun scorching

If All Else Fails

• Sick plants should be separated from healthy plants to avoid cross contamination
• Always wash your hands and tools after handling a sick plant.
• Develop a callous attitude to badly infested or diseased plants. Accept some failures and destroy them saving your time and energy for healthy specimens.

Mildew is a white powdery fungus that looks unsightly on these leaves. Mildew is a sign of stress in a plant and usually arises from damp air with poor circulation. It is prevalent in my garden now Autumn is here in force. It is of less concern in winter as the cold will take care of the current problem until next year at least.

Some plants are more prone than others. My Phlox, Roses, Michaelmas Daisies and Azaleas have varying amounts of mildew at the moment.

Prevention improves by increasing the air flow and prune to allow that to happen. Water the ground not the leaves and mulch to keep moist.
Treatment by fungicide may not be eco-friendly so try a spray made from a tablespoon of baking soda in a gallon of water with a squirt of washing upo liquid to help it to stay on the leaves.
The fungus will not spread from one species to another but will linger in the soil so destroy infected plant matter or put up with the problem.
Keep roots of susceptible plants very well watered through spring and summer..
Seek out mildew resistant varieties and avoid late feeding of high nitrogen fertilizer creating young sappy growth.

Understand more about mildew in your garden

Summer is over and we had the first Autumn frost last night 26th September. It was only a light frost and we have some cloud cover for the next few nights so it won’t be as cold tonight. Still I set-too to protect some plants.

Winter Plant Protection

• Tender plants can be protected in a frost free environment. Conservatory plants left out for some summer sunshine should be brought back inside. This is true of Citrus fruit trees and Pelagoniums.
• Insulate your greenhouse with bubblewrap and install a heater for really cold nights. Aim for a minimum temperature of 37°
• Lift tender rhizomes of Cannas and Gladioli corms.
• Prepare hessian or sacking to wrap the centre of tender plants like Tree Ferns and Palms.
• Reduce watering and keep pot plants a bit on the dryer side.
• Mulch or cover the growing crowns of perennials with bracken, dry leaves or compost.

Winter Maintenance Tips

• Put terracotta pots on feet or raise onto bricks so they do not freeze to the earth or paths. Bring in none frost proof pots.
• Clean up paths, greenhouse glass, garden furniture, bird feeders etc.
• Retie or stake trees that may suffer from wind rock.

Causes of Winter Damage

• Prolonged excess damp can be fatal to pot plants. In winter there is little or no drying effect.
• Snow can break the branches of trees and the weight can damage conifers and evergreens.
• Frost will damage soft fleshy growth easier than it will kill ripe twiggy growth. Camillia growers will know what frost can do to blossom.
• Climate changes, prolonged cold snaps, unseasonal spring or summer weather and other changes can create ‘plant stress’ that shortens the plants life.

Other tips – Leave on holiday for hotter climates and return in spring.

 Habits of Red Spider Mites

• Red Spider mites do not spin good webs. Proper spiders make symmetrical and neat webs.
• You can recognise infections if the web is feeble and scraggy with tiny white flecks on some of the strands (this is dead mite skins).
• You can also detect mites by placing white paper under a leaf and tapping several times. If infested some of the mites will fall from their hiding under leaves and away from direct light on to the paper.  If you see red dots scampering around and you have your work cut out although they start green in spring turning red later in the summer.
• Mites pierce the skin of leaves and suck sap causing paling then red or yellow spots. This then leaves a fine white powder and leaves begin to fall off.

Problem Control and Prevention

• Few plants are immune and indoor Cistus, Dracaena, Citrus, Podocarpus and even Aspidistra are susceptible.
• Tomato and greenhouse plants also suffer.
• Crocosomia, dahlia, fuchsia, runner beans and soft fruit are also susceptible.
• Mite move easily from plant to plant and are so small that drafts can blow them from one plant to another. Isolation is the first option.
• Mites find a hot dry environment a delight, whilst mites abhor humid conditions so try frequent misting to discourage mites.
• Submerging plants in a stream of warm water or hosing off out doors may help.
• Spray with soapy water or plant oils paying attention to the undersides of leaves and leave to dry.
• Biological control with Phytoseiulus persimilis is effective in warm areas.
• Malathion pesticide can be used, mix with water and a drop of soft soap but keep the spray away from cacti and ferns.
• Systemic granular pesticide is a last alternative.

Sources
Tetranychus urticae Female of the red form of the spider mite
Scale : mite body length ~0.5 mm
Creative commons by Gilles San Martin, on Flickr
Chuck Crandall ‘Whats wrong with my plant?’

RHS the Tetranychus urticae is also known as Two Spotted Spider Mite