Knowing your climate zone will help you decide the best time to sow the vegetables, herbs and flowers you want to grow, and which varieties should perform well in your garden. Growing plants that are suited to your climate zone will usually give you the best results in your garden.
Given the right conditions, a citrus tree can reward a gardener with a productive crop while enhancing the garden with its lush appearance. While most citrus varieties are relatively sturdy and can fend off many kinds of insect attention, theyre particularly susceptible to one particular species.
Citrus leaf miner, or Phyllocnistis citrella, is a common pest that attacks all varieties of citrus. While an infestation is rarely fatal for an established tree, it can cause unsightly damage, reduce yields, and potentially weaken plants, leaving them more vulnerable to disease or other insect pests.
Leaf miners are a common pest that can damage many plants, including the beautiful autumn sage. These tiny larvae tunnel between the leaf surfaces, munching away at the inner tissues and leaving behind unsightly trails or blotches on the leaves. An infestation can quickly get out of hand, causing extensive foliar damage, plant stress, and flower/fruit loss.
If you’ve noticed meandering pale lines, blotches or browndead areas on your autumn sage, it likely has leaf miners. The good news is there are several effective control methods to get rid of these pests and restore the health and vigor of your plant. In this article, we’ll cover how to identify leaf miners, cultural and natural treatments, conventional pesticides, and prevention.
How to Identify Leaf Miners
Carefully inspect the upper and lower leaf surfaces of your autumn sage Look for
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Winding or blotchy pale trails between the leaf surfaces. These are the feeding tunnels created by larvae.
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Brown dead patches or dried leaf edges. This happens when the larvae feed close to the edge, severing the tissues.
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Small yellow, black or green larvae inside the tunnels (visible with a hand lens).
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Tiny black fly eggs laid singly on leaf undersides
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Adult flies hovering around foliage. These pests are very small (1/16 to 1/8 inches long) and usually black or gray.
Leaf miners may only affect certain sections or branches if the infestation is light. So inspect all over for early signs of an attack.
Cultural and Natural Treatments
For mild leaf miner damage, non-chemical methods are usually effective. Here are some cultural and natural remedies to try:
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Water spray: Blast leaves with a strong jet of water 2-3 times per week. This can dislodge larvae and exposes them to predators.
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Prune out damage: Remove and destroy badly infested leaves and shoots. This eliminates larvae and eggs before they spread.
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Keep soil dry: Leaf miners thrive in moist conditions. Allow the soil to dry slightly between waterings.
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Beneficial insects: Ladybugs, lacewings, parasitic wasps and other beneficial predators feed on leaf miner larvae. Attract them with flowering herbs like dill, fennel and parsley. You can also buy them from garden stores.
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Neem oil: This organic insecticide disrupts larval growth and adult reproduction. Mix 1-2 tsp neem oil + 1 tsp liquid soap in 1 quart water. Spray leaves, especially undersides, every 7-10 days.
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Insecticidal soap: Direct contact with foliage kills larvae on contact. Spray leaves thoroughly every 5-7 days.
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Diatomaceous earth: This abrasive powder desiccates and kills larvae. Dust on leaves or mix 1-2 tbsp into the top few inches of soil. Reapply after rain or watering.
Be patient, as it takes time for natural methods to take effect. Focus on prevention next year by keeping plants healthy and inspecting regularly for early signs. Dispose of heavily infested plants if pests persist.
Chemical Treatments
For heavy leaf miner infestations, or if natural remedies have failed, chemical control is warranted. Spinosad (Captan, Monterey Garden Insect Spray) is an effective biological insecticide for leaf miners. It’s low toxicity to mammals and safe for bees. Spray foliage to the point of runoff every 7 days for 2-3 weeks.
Neonicotinoids like imidacloprid (Merit, Bayer Advanced) provide systemic protection against leaf miners. Apply as a soil drench or granules around autumn sage in spring, before damage begins. These chemicals can affect bees, so use them as a last resort if other options fail.
No matter what pesticide you use, fully cover the upper and lower leaf surfaces for best results. Always follow the product label for proper usage and precautions. Avoid spraying open flowers to protect pollinators. Chemical treatment is most effective against young larvae; mature ones are harder to control.
Prevention
An ounce of prevention is truly worth a pound of cure when it comes to leaf miners. Here are some tips to avoid problems next year:
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Grow autumn sage in full sun. Leaf miners thrive in shadier, more humid conditions.
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Space plants properly to allow air circulation and rapid drying after rain/watering.
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Fertilize monthly with a balanced organic fertilizer to keep plants vigorous. Stressed plants are more susceptible.
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Prune autumn sage after flowering to remove old wood and improve air circulation.
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Weed and mulch around plants to reduce competition. Grass and weeds harbor leaf miners.
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Check for leaf miners in early spring. Take action at the first signs of trails or stippling damage.
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Remove and destroy infested leaves/shoots immediately before larvae mature.
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Introduce beneficials like ladybugs and lacewings early in the season. Their larvae prey on young leaf miners.
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Cover plants with floating row cover fabric at the start of spring. Excludes adult flies from laying eggs.
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Rotate susceptible herbs like basil each year to prevent buildup of leaf miner populations in soil.
With diligence and a combination of these cultural, natural and chemical control methods, you can get rid of leaf miners on autumn sage and restore the health of your plant. Just be sure to take preventive measures next season to avoid renewed attacks on this beautiful ornamental sage.
Frequently Asked Questions
What are leaf miners?
Leaf miners are the larvae (immature stage) of various flies, moths and beetles that feed inside plant leaves, creating winding tunnels between the leaf surfaces. Common leaf miner species include serpentine leaf miners, pea leaf miners, and citrus leaf miners.
How do leaf miners damage plants?
Feeding by larvae inside leaves causes ugly trails, blotches and brown dead patches. Heavy feeding stresses plants, ruins the appearance of ornamentals, and reduces fruit/flower yields. Leaf miners make leaves more prone to disease as well.
What plants do leaf miners attack?
Many vegetables, herbs, ornamentals and fruit trees are susceptible, including autumn sage, tomatoes, squash, peas, basil, citrus, apple, birch and more. Each leaf miner species has preferred host plants.
Can leaf miners kill plants?
They don’t often kill mature plants outright, but leaf miners can seriously weaken and reduce the vigor of sensitive vegetables like lettuce, spinach and chard. Repeated infestations year after year can potentially kill young or already stressed plants.
What are leaf miner natural enemies?
Ladybugs, lacewings, hover fly larvae, predatory stink bugs, parasitic wasps and pathogenic fungi help keep leaf miner populations in check naturally. Avoid overusing chemicals that would harm these beneficial species.
Can leaf miners infest indoor plants?
Leaf miners are much less common indoors, but they can sometimes hitchhike in on infested plants or cuttings. Keep susceptible houseplants like citrus isolated from outdoor specimens. Inspect carefully for trails and castoff larvae/eggs.
Are leaf miners harmful to humans?
No, leaf miners don’t bite or transmit any diseases to humans. The only harm is the damage they cause to plants we use for food and ornamental purposes. Their trails in edible leaves are purely cosmetic.
How do you find leaf miners inside leaves?
Hold leaves up to bright light – this helps spot winding trails inside. Or place leaves against a solid background like black cardboard, making the trails stand out more. Magnifying glasses also help discern tiny larvae in tunnels.
Can leaf miners can come back after treatment?
Yes, it’s hard to kill every single leaf miner. Some may survive in soil to reinfest plants, and flies can migrate in from elsewhere. Repeat chemical or natural treatments to kill survivors before they multiply. Maintain vigilance.
How to Use Climate Zones
First, find your climate zone using the map or descriptions below. Next, refer to our sowing chart, which provides approximate sowing times for our most popular seeds for each climate zone.
While knowing your climate zone is helpful when planning your garden, there are many other factors that may affect how your plants grow, including unseasonal weather conditions, the specific microclimate of your garden and how you care for your plants. You know your garden better than us, so if a different climate zone seems to ‘fit’ your garden better, go ahead and use it as a guide.
Our climate zones cover huge areas of Australia, so we recommend gardeners also consider their local conditions when planning what and when to plant. For example, gardeners in alpine areas have shorter growing seasons than gardeners in cool coastal areas, even though both alpine and coastal areas are included in our ‘Cool Temperate’ climate zone. We recommend gardeners in cool regions look at the ‘days to maturity’ information provided for each variety and choose those that will mature in a short (6-12 week) growing season.
- Includes: Darwin, Cairns, Townsville, Exmouth
- High humidity summers with most rainfall in summer and dry, warm winters. Includes northern Australia from Exmouth (WA) across to south of Townsville (Qld).
- Set as my climate My climate
- Includes: Alice Springs, Mildura, Albury-Wodonga, Shepparton, Wagga Wagga, Dubbo
- Hot dry summers, winters can be warm or cool depending on the region. Includes a large area of central Australia from the WA coast to Charleville (Qld), Tamworth (NSW) and Albury-Wodonga (NSW/Vic).
- Set as my climate My climate
- Includes: Brisbane, Bundaberg, Coffs Harbour, Gold Coast, Hervey Bay, Mackay, Rockhampton, Sunshine Coast
- Warm humid summers with high summer rainfall and mild winters. Includes coastal Queensland and northern NSW from north of Mackay to just south of Coffs Harbour.
- Set as my climate My climate
- Includes: Sydney, Perth, Adelaide, Newcastle, Toowoomba, Central Coast NSW, Wollongong, Bunbury
- Moderate humidity and reliable rainfall, with four distinct seasons. Includes coastal areas from north of Port Macquarie to south of Woollongong in NSW, coastal SA and the southeastern coast of WA.
- Set as my climate My climate
- Includes: Melbourne, Canberra, Hobart, Launceston, Ballarat, Bendigo, Geelong, Mt Gambier
- Low humidity with most rainfall in winter; hot dry summers and cold winters. Some regions will experience frosts and snow. Includes coastal areas of south-eastern Australia and alpine areas of Victoria, NSW and Tasmania.
- Set as my climate My climate
What if I can’t find my climate zone? If you can’t locate your zone from looking at the map or the descriptions on this page, we suggest that you think of an area that has a climate that’s similar to yours and use the zone for that area as a guide.
What if I live on the border of two zones? If you live near the border between two zones we suggest you read the descriptions for both zones and decide which best describes the climate where you live. Depending on the microclimate in your garden, you may be able to grow a wider range of plants over a longer season than others in your zone. Lucky you!
What is a microclimate? A microclimate is a small area where the temperature or humidity differs to the climate of the surrounding area. For example, if you live in a climate zone where frosts are common but your garden is protected by buildings or large trees, your garden may be frost-free. Similarly, if you live in a warm temperate zone but your garden is at a high altitude your microclimate may have more in common with the cool temperate zone, so use this as a guide when deciding which zone is relevant to you.
Can I grow varieties not listed for my climate zone? While our climate zones and sowing chart will help you decide what is suitable to plant in your garden, they provide general guidance only. We recommend you start by sowing seed that’s recommended for your climate zone; once you get a few successes under your belt you can experiment with varieties in neighbouring zones and see how you go – gardening is all about experimenting after all!
Given the right conditions, a citrus tree can reward a gardener with a productive crop while enhancing the garden with its lush appearance. While most citrus varieties are relatively sturdy and can fend off many kinds of insect attention, theyre particularly susceptible to one particular species.
Citrus leaf miner, or Phyllocnistis citrella, is a common pest that attacks all varieties of citrus. While an infestation is rarely fatal for an established tree, it can cause unsightly damage, reduce yields, and potentially weaken plants, leaving them more vulnerable to disease or other insect pests.
What Is Citrus Leaf Miner?
Citrus leaf miner is a native of southeastern Asia and was introduced to Australia sometime in the early 1900s, quickly becoming prevalent thanks to its fast breeding, with up to 15 generations a year. In its adult form, the citrus leaf miner is a white moth with minor brown markings, measuring a mere 4mm across its wingspan. Moths are nocturnal and live for only a few days to weeks, meaning they are rarely seen even during heavy infestations.
The insect causes problems at the larval stage. The eggs are laid on the undersides of the citrus leaves, and after hatching, the 3mm greenish-yellow, translucent larvae tunnel into the leaves to feed, giving rise to the leaf miner name. The tunnelling creates meandering, silvery trails which are usually the main way that the infestation is detected. In severe cases, the tunnelling can cause young leaves to lose structure and distort. Because the larvae are hidden within the leaves, the caterpillars themselves are rarely seen. While established trees can usually shrug off the damage, younger trees with fewer leaves are more seriously affected.
The larval activity is highest mainly in late summer or autumn, before fruiting and when theres plenty of tender foliage to feed on, although the pest can appear whenever fresh growth is bountiful. Once the leaves have matured and coarsened, theyre no longer useful as a food source, and the adults will stop laying their eggs.
After the larvae have had their fill, which usually takes 5 to 21 days, theyll form slightly smaller 2.5mm long brown pupae. These are usually hidden within rolled-over leaf margins and bound up by silk. The adult moths typically emerge in one to three weeks, starting the cycle again, though the citrus leaf miner may overwinter in either the larval or pupal stages.