It is inevitable, at some stage in your vegetable garden, you will encounter garden pests and/or diseases that even the most experienced garendener has to deal with. This is by no means intended as a comprehensive guide to vegetable garden and fruit pests, primarily because there are just so many, but also, because some don't cause problems in every climate zone, let alone country. So the following list (that will continue to be added to) reflects those that I have to deal with in our temperate climate.
The following list is divided into three sections, the pests - those that crawl & fly, chew & suck or just plain peck, the insects and birds and the problems that occur caused by disease. The final section, a guide to remedies that I have or do use. If there is an environmentally friendly alternative, I'll list it, but, you need to consider all of the information here as a guide.
You should complete your own investigations as to the most appropriate solution for you. Grow-your-own-vegetable-garden.com assumes no responsibility for any outcomes that result from any information listed here.
Blossom End Rot
Blossom end rot, as seen here on some of my early developing tomatoes, is normally blamed on a calcium deficiency in the soil. This is however, not the sole cause and the problem can be exacerbated by a combination of a couple of factors. it first appears as a small dark spot on the bottom of the fruit where the remains of the flower are and grows in size as the fruit develops and rots from the base up. The fruit will always end up as inedible and should be removed from the plant.
The three main factors that cause this problem are calcium deficiency in the soil, excessive fertilising with nitrogen and inconsistent moisture levels.
In Australia, soil calcium levels are notoriously low and this combined with the potential for high moisture stress in hot temperatures usually cause the disease.
In our case, this was the cause. New beds that had insufficient calcium added before planting combined with a couple of extreme temperature days resulted in some fruit affected as you see here. The high levels of transpiration (water evaporation from leaves) can cause localised deposits of calcium in the leaves instead of the fruit and therefore a shortage (when calcium is available to be taken up in the first place) Excessive nitrogen results in rapid foliage growth, which in turn increases the transpiration and the result is the same. NB: excessive moisture can also cause the problem, so don't be tempted to over water either.
Prevention is the best cure, as once affected, the damaged fruit cannot be saved, although removing it can prevent further problems. Dressing soil with dolomite lime and or gypsum several months prior (I usually do so 2-3 months ahead) to planting will allow time for the soil structure to settle and ensure calcium is available to the developing plants. Check the soil PH before treating. You should aim for a PH reading of between 6.0 and 6.5. If the PH level is ok, then apply gypsum to increase calcium levels (lime affects PH levels). How do I know if I need to add calcium before planting? The easiest approach here is assume you need it! If the bed hasn't been given any lime in the last 2-3 years of growing, it is most likely deficient. Dig the lime into the soil to around a depth of 20-30cm.
There is no real cure for this disease once it is exhibited, but you may be able to prevent further occurence if you act quickly when first spotted.
Remove the affected fruit and dispose of it. Apply a dresssing of either dolomite lime and water in or use a liquid gypsum and apply both as per the manufacturers dosing rates. Alternatively, apply a commercially available tomato food as per recommended dosing rates on the packaging. Ensure the plants are watered evenly and regularly to prevent mositure stress. Mulch the plants to help minimise the evaporation from the soil. Avoid excessive pruning of the plants as this also exacerbates the problem.
See the Tomato page for more general tomato information
See the Tomato e-book for tips and information on growing your own Tomatoes
White Powdery Mildew
White Powdery Mildew is a fungul disease caused by fungul spores that are present in the air. Its attack on plants is exacerbated by a few environmental conditions, namely limited air flow around affected plants and high levels of localised humidity. These two conditions provide perfect conditions for the development of the spores. The mildew shows initially as white "furry" spots and if left untreated rapidly spreads to completely coat the leaves of the plant. It typically affects plant in the cucurbit family (pumpkins, melons, zucchini, cucumbers) and also peas, but can affect any plant exposed.
The mildew can severely affect the growth and development of the plant and considerably reduce the development of fruit.
I have found prevention of outbreaks of mildew to be next to impossible, but, there is a bit that can be done to minimise the problem.
Firstly, ensure adequate spacing between plantings. Overcrowding, reduces the airflow around the plants and provides the first of the ideal conditions for the spores. Secondly, never water plants from above. This artificially increases the humidity levels, providing the second condition. Contrary to popular belief, dry climate areas are not immune to the problem as localised humidity can result from warm days and dew overnight.
There are a number of commercially available fungicide sprays available if you choose to use them, but, most if not all are poisonous and I'm not one for spraying poisons on food crops, irrespective of witholding periods.
A mixture of milk and water sprayed over the affected foliage has proven to be effective. Ratios from 10-50% have been reported to be effective. Action should be taken as soon as an outbreak is spotted, then repeated at 5-7 day intervals. In addition, removing affected leaves (within reason), including all affected, fallen leaves and disposing of them (not composted)will also help.
Things that grew in the night!