Vegetable Gardening for Beginners

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Citrus leafminer – Phyllocnistis citrella

citrus leafminer adult and damage caused

Leafminer is native to eastern and southern Asia and is now widely distributed where citrus is grown in Asia, Papua New Guinea, Australia, northern and central Africa, and Florida in the United States of America. The moth was first recorded in Australia in and around Darwin in the Northern Territory in 1912.

Citrus leafminer is the most common pest that attacks all varieties of citrus.


citrus leafminer adult

Citrus Leaf Miner Adult

The adults are small, delicate moths with narrow paired forewings and hind wings fringed with long hairs. The upper surface of each forewing has a black dot at the tip, and irregular dark lines separating an inner region (covered with silvery scales) from an outer region (with silver, light yellow and brown scales). The hind wings are narrower than the forewings and are covered with silvery scales. At rest, with their wings folded lengthwise, the moths are about 2 mm long. In flight, their wingspan is about 4.5mm.

Because flight generally occurs at night, the adults are rarely seen in daylight except when they are disturbed, generally by human activities. When this occurs, flight is short and rapid. Females are slightly more common than males. Both sexes emerge from their pupal stage during the early morning hours. Mating generally occurs at dusk and in the early evening about 9 to 12 hours after emergence. Adult female moths start laying eggs about 24 hours.

CLM larvae

Citrus Leaf Miner Larvae


It is not the adults that cause the most aggravation to home gardeners but the larvae.

Citrus leafminer larvae feed by creating shallow tunnels, or mines, in young, immature leaves of citrus trees.

CLM damage flushing foliage

Citrus Leaf Miner damage flushing foliage


A common description is: “My citrus leaves are curling!”

With further investigation it is discovered that the new leavers are twisting and distorted but also have the tell tale sign of “silver, wiggly, snail trail looking lines”.

The silver wiggly lines on the leaves are the first sign. The leaves then become distorted. This inhibits their photosynthesising ability. This won’t kill trees, but they will be stunted and unhealthy with a reduced yield. When fully grown, the larvae will curl the leaf around for protection while they pupate.

Such infestations usually only occur in late summer and autumn, and are often related to low natural enemy activity.

Because infestations are limited to flush growth, predominantly in late summer and autumn, their severity can be reduced by:

  • Fertilise in early Spring to promote a flush of new growth in spring when the pest is either not present or rather scarce. A secondary fertilise (only small amount) in Autumn if required.
  • Pruning of late summer and autumn flush growth can also be of use to regulate and get rid of unattractive infestations on trees.
  • Cut off any curled, damaged or rolled leaves that could be hiding the pupae.
  • Spray with horticultural oil early morning to deter the moth from laying new eggs. Be aware that the oil won’t kill the larvae but simply deter.
  • Natural enemies: These include small parasitic wasps and predators such as lacewings.

Pests and Diseases

garden pests

All gardeners at one time or another have lovingly cultured a garden only to have it succumb to the ravages of pest and/or disease. But before we reach for the chemical sprays take into account a few simple things that will make a massive difference in diminishing or eradicating unwanted pest and disease.

First and foremost – A functioning garden design that takes in account: airflow, sun tracks, wind tracks, shadows from larger surrounding structures and trees, irrigation options and useability.

  • Adequate airflow throughout the garden.
  • Adequate sunshine (morning sun and then at least 6 hrs).
  • Minimal soil disturbance and compaction – make designated walkways and stick to them.
  • Wise water distribution and application practices. Water in the morning preferably. This will hydrate the plants for the duration of the day and will decrease the  chances of bacterial and fungal issues. Water only around the plants roots and not over the foliage. If you water over the foliage you can encourage bacterial spot to prosper etc. Water deeply not just a light little spray. This will encourage plant roots to dive deeper into the soil. Wet leaves does not mean wet soil.
  • Great soil nutrition – practice crop rotation and supply adequate macro and micro elements.
  • Companion planting to discourage unwanted insects and attract BENEFICIAL INSECTS.

The NASAA Organic Standard (December 2004) defines organic agriculture as “a holistic system built upon natural ecological processes”. These ecological processes include the biological activities of all organisms living within the soil as well as those living above the soil surface. Of all such organisms, of which there are many tens of thousands of different types, only a relatively small number cause problems in our crops. In fact, most are beneficial and some are essential to the health of most plants. Consequently, we need to be mindful of the disturbance to the overall ecological balance of organisms living within our garden caused by the use of sprays or other methods to control pests and diseases. After all, it is the maintenance of that ecological balance which is the key to a productive organic garden.


All too often the heavy handed use of either chemical or organically certified products can ultimately result in more harm being done then good. Some sprays are indiscriminate and will kill ALL garden pests, good and bad alike, just as other organically accepted products can upset the vital balance between beneficial bacteria and fungus’s present within the soil. Try to choose sprays that target select insects/diseases rather that broad spectrum sprays that will kill indiscriminately
Planting flowers and herbs that attract beneficial insects will help in tipping the balance in your favour. If there’s “good bugs” present to deplete the”bad bugs” than they will be doing the job of pest control for you! Investigate which insects are “good” or “bad” before spraying.

Constant maintenance and monitoring of your garden will help dramatically.

  • Remove all unwanted weed species that could be harbouring the “bad bugs”.
  • Mulch as required to help keep weeds down in the first place.
  • Water regularly and adequately to reduce plant stress.
  • Regular fertilising of a balanced organic fertiliser will keep plants humming along.
  • Remove all fallen or older fruits etc.
  • Observe and act on unwanted pest arrivals before they get out of hand.

The 5 components of soil are:

  • Air – adequate air flow and soil drainage.
  • Water – adequate soil moisture holding content.
  • Minerals and trace elements – providing plant available balanced fertilisers.
  • Organic matter – to provide optimum environment for soil flora and fauna to flourish.
  • A balance of micro and macro organisms existing both above and within the soil structure.

Vegetable gardening is neither hard nor overwhelming once you have the correct mental tools. By observing and recording your journey throughout the year you will help yourself in following years by recognising trends within the veggie patch. Correct information relevant to your climatic region and local micro climate is the key. The more you research, the easier it all becomes.