Watch for and treat crop pests

TARGETS: Tomatoes beware - psyllids are on the prowl. PICTURE / THINKSTOCK

Happy New Year to you all. The holiday period has been a real treat this year with brilliant fine and settled weather, unlike last year when we had a lot of rain.
The good weather has been great for allowing time outdoors in the garden. Plant growth has been good. This is particularly noticeable in the vegetable garden where you can see the plants grow considerably each day and of course, most alarmingly, how much bigger those weeds have become!
It has been a fantastic time of harvesting the fruits of one's labour with tomatoes, capsicums, beans, courgettes, cucumbers, lettuce, broccoli and more, coming out of my vegetable garden over the past few weeks, as well as strawberries, raspberries and the absolutely brilliant berry delight.
The billington plums are just starting to ripen now though I see the birds are getting keen and checking them out also!
We must be wary of humid weather. This creates problems of its own in the form of mildew and blight. My cucumbers have been showing signs of mildew, the removal of infected leaves and spraying with Yates Guardall has helped to limit the spread of this disease, as well as control whitefly and aphids.
Unsettled weather shows up the strengths and weaknesses in a garden. The strong winds in December took out a few taller shoots on my standard roses that were sporting flowers, and seeing a couple of lurching delphiniums reminded me that staking plants as protection from wind rather than later, as an effort to save the plants, is always a better strategy.
Read this if you are growing - tomatoes, potatoes, tamarillos
If you are not aware of the potato/ tomato psyllid then read the info below with extracts from Plant and Food Research. Further information can be gained from http://www.biosecurity.govt.nz/pests/potato-tomato-psyllid or come and talk to us in the garden centre.
The relatively new pest, potato / tomato psyllid is prevalent in Wanganui and if left untreated can devastate your crop. It can be easily treated with the bee friendly Yates Mavrik or new Yates Success Ultra.
In potatoes the tops grow great with little or no indication of a problem but when lifted only marble sized potatoes were found. The potato/tomato psyllid releases a toxin while sucking on the stems and leaves of potatoes and tomatoes preventing the spuds or fruit from developing and you end up with small useless fruit or spuds.
Psyllids feed like aphids. They suck the sap and excrete the excess water and sugar as honey dew or as a solid waste (psyllid sugar). Nymphs and possibly adults inject a toxin into the plants when they feed.
Visually psyllid sugar is the symptom that you are most likely to see on your plants once they are infected. The toxin causes discolouration of leaves and the plant to become stunted exhibiting "psyllid yellow" and "purple top". Leaf edges upturn and show yellowing or purpling. The plant's internodes shorten and new growth is retarded. At this stage the plants are best removed and disposed of to limit spread to other plants.
Adult psyllids are strong fliers and are dispersed by the wind.
It is interesting to note the damage reports from Wanganui gardeners over the past few years here regarding potato crops (five years now). Early potatoes planted and harvested prior to Christmas generally avoided damage, while main and late croppers needed treatment with Yates Mavrik or Yates Success Ultra to control the psyllid. Psyllid damage to tomato crops in Wanganui home gardens became evident in the past three years and the early reports of damage this season, back in early November, indicate the insect is prevalent on tomato plants and will need to be treated to reduce incidence of crop damage.
The plants affected are all members of the solanum (potato and tomato) family.
A number of gardeners around Wanganui reported poorer crops of tamarillos during the last three winters. It is likely that the psyllid, while not active during winter, would have been present during late summer and autumn when tamarillo fruit is forming and caused the poorer fruiting of these last season.
Overseas it is reported that capsicum and eggplant have also been affected.
Other control methods to employ include:
For greenhouses
•Hang yellow sticky traps close to the top of the plant canopy to capture adults.
•Hang yellow sticky traps by vents to check for adult psyllids entering from outside.
•Check plants weekly for signs of eggs, nymphs and psyllid sugars.
•Check plants for psyllid yellows symptoms. This is yellowing of leaves, curling up of leaf edges and shortening of internodes.
In outdoor crops
•Check plants that display symptoms, such as stunted growth, psyllid yellows or purple top, for the presence of psyllid sugar and psyllids.
•Place sticky yellow cards at field margins near the tops of tomato plants to capture adults.
•Remove and destroy affected leaves. Plant material should be kept in a covered container until removed from the property. If kept on the property, plant material should remain covered with edges sealed for 4-6 weeks. Old crops being removed should be treated the same way.
•Remove and destroy alternative host plants (nightshade).
House flies
These are an annoying downfall of summer; they buzz around the house, sit on food, people and furniture and to use the term of a friend of mine, "drive one nuts". They are a result of the summer months where temperatures provide ideal breeding conditions.
Flies come from the outside. The treatment strategy for flies is to reduce the outside attraction if at all possible. The main attractions are odours such as those caused by pet droppings, animal droppings, stagnant water, mould, mildew and household rubbish.
Last summer I discovered a source that I hadn't considered that was attracting more flies: my beautiful lush pittosporum mountain green hedge was buzzing with flies. Upon closer inspection I discovered the hedge was covered in aphids and psyllid (different to potato/tomato psyllid) and because of the volume of infestation there was a lot of insect by-product which is a sugary excretion. This was attracting flies which then visited my house only metres away.
This summer I have been keeping an eye on it and so far the aphid population has not increased as early as last year, probably thanks to a good cold winter last year. Interestingly but not surprisingly my hedge is looking a lot better this year with the growth tips not showing shrivelling insect damage. So far so good, I also have fewer flies!
Overwatering house plants can increase fly populations inside the home due to warm and moist organic matter (potting mix) providing another area for breeding. Reducing watering and keeping the plants drier and/or spraying the mix with an insecticide three times over a 10 day period to break the lifecycle is effective. Yates Nature's Way Fruit & Vegie Gun is a natural pyrethrum-based insecticide for use on vegetables, fruit, rose bushes, indoor plants and outdoor ornamentals. It is fast acting and kills a wide range of pests including aphids, caterpillars, thrips, earwigs, whitefly and leaf hoppers.
Relax, enjoy the garden and have a good week
Gareth Carter is General Manager of Springvale Garden Centre.