Download Carrots - Garden Science

Roses
The unmistakable beauty and fragrance of the rose have made this flower one of the
most well recognised symbols of life and love over the centuries. Roses belong to the
Rosaceae or the rose family that includes over 3000 species with over 100 genera of
plants that grow as trees, shrubs climbing plants (e.g. vines) and perennial herbs
worldwide. The Rosaceae family consists of dicotyledonous plants that have alternate
leaves and flowers with five petals and numerous stamens (the male pollen-bearing
part of a flower). A few of its most familiar genera include stone fruit (e.g. cherry and
peach), pip-fruit (e.g. apples and pears), strawberries, and brambles (e.g. raspberry
and blackberry).
Where do roses come from?
According to three million year old fossilised records, roses are undoubtedly one of
the oldest known flowers on this planet. The original roses, named wild or species
roses, have a quite simple appearance. They have a single flower with five (or in
some cases four) petals and are native to temperate climatic areas of the Northern
Hemisphere. Over time, two separate groups of species and hybrids were
propagated (e.g. from cuttings, suckers and runners but not by seeds) from these wild
roses: the European/Mediterranean group (blooms once per year) and the oriental
group (blooms throughout the year). The first garden roses most likely originated in the
Middle East. Their popularity spread throughout Europe from ancient Greece
and Rome.
At the end of the Middle Ages, European plant breeders (especially Dutch and
French) learned that roses can be propagated by seeds. This discovery led
horticulturalists to cross pollinate flowers to create seeds of new and more desirable
varieties of roses (e.g. year-round blossom, different colours and petal numbers). The
hybrid Musk, hybrid Perpetual and hybrid tea roses developed in the 19 th century led
to the modern roses of today.
Growing roses throughout the year
Winter (June, July, and August)
•
Ideal time to plant bare-rooted roses.
•
Winter prune established plants to remove dead anddiseased wood. Prune
the remaining growth down to approximately two-thirds of its height.
•
The bushes and surroundings can be sprayed to prevent fungal spores from
‘over wintering’ on the bush or in the ground using copper oxychloride, winter oil, or
lime sulfur.
Spring (September, October, and November)
•
Mulch beds to control weeds and retain moisture during dry summers. Apply
well rotted
manure mixed with garden compost.
•
Start spraying for diseases and insect deterrents at leaf-break and continue at
14-day intervals using either low-toxic organic or chemical controls.
•
Apply base fertilisers in September and three-month slow release fertilisers in
October.
•
Dead-head flowers as needed.
Summer (December, January, and February)
•
Dead-head old flowers to encourage new growth and repeat flowering.
•
Irrigation: Roses do not like to dry out. They need at least one heavy watering
once a week. Do not wet the foliage, although moisture on leaves can deter mites.
When managing pests and disease on rose plants:
•
identify the pests and diseases present on the plants
•
seek information on the life cycles of all the diseases
and insect pests of roses
•
identify the natural beneficial insects present
•
seek information on the life cycles of natural beneficial
insects
•monitor weather conditions because they can affect the diseases that occur
Symptom
Control method
Rust
Rust derives its name from the orange-brown
spore masses that the fungus produces.
The upper surfaces of leaves become speckled
and sometimes blotched with yellow patches.
On leaf under surfaces there are correspondingly
orange-brown spots. If stem infections are heavy,
the stem may be ring-barked, resulting in
die-back of the upper portion of the stem.
Apply preventative
fungicides from leafbreak in spring and
remove all infected
leaves and stems.
Black spot
On leaves circular black spots up to 1 cm in
diameter with fringed margins appear.
Spots vary in number and are usually on the
upper surface. Yellowing of a portion or all of
the leaflet is soon followed by defoliation.
Apply preventative
fungicides from leafbreak in spring. Remove
all infected leaves.
Powdery mildew
Affects only the growing tips in dry/hot conditions,
found in mid-summer (January-February).
Apply preventative
fungicides to susceptible
cultivars at the beginning
of January before
infection occurs. A
mixture of baking soda
and mineral oil has been
successful in preventing
the spread of powdery
mildew.
Phragmidium mucronatum
Organism: Fungus
Diplocarpon rosea
Organism: Fungus
Sphaerotheca pannosa
Organism: Fungus
Important notes on disease control:
Most fungicides are preventative. The key period to control diseases is in spring or
early summer, between September and December. By keeping infection levels low
during this period, the need for control is not as critical later in the season.
Rose cultivars differ in their susceptibility to disease. Identify those that grow best and
replace any that are disease-prone.
Note
•
Genera is the plural term for more than one genus
(i.e.
a
group
of
organisms
that
are closely related and share similar characteristics).
•Family is a broader taxonomic group that contains one or more genera.
Camellias
History
The genus Camellia was named by the Swedish Botanist, Carolus Linnaeus. He
developed the binomial system of plant naming that is still in use today. The genus
Camellia was named in honour of a 17th century Jesuit missionary, Joseph Kamel,
which is Camellus in Latin. All of the 267 recorded species within the genus originated
from Asia, where they had many uses, including ornamental, cosmetic, and culinary
(e.g. in tea blends). They are also a source of oil and provide fuel in the form of highgrade charcoal.
Nutrient value
Camellia leaves in general consist of polyphenols, mainly flavonoids (water-soluble
plant pigments), vitamins, volatile oils, and caffeine. The flavonoids, especially
catechin or epigallocatechin gallate, are known to contain a potent antioxidant as
well as anti-cancer substances. They also protect against digestive and respiratory
infections. Camellia tea is also well known for its anti-inflammatory, antiviral,
antibacterial, anti-thrombotic (stops the formation of a blood clot within a blood
vessel) effects and cholesterol lowering properties. It assists in weight loss by
speeding up fat oxidation, and lowers high blood pressure. It is a perfectly natural
‘health’ drink, and when consumed on its own it has no calories.
Scientific advice on plant care
Plants need to be grown in humus-rich, porous soils that are slightly acidic (pH 5.56.5). They also need good sunlight and high humidity with temperatures below 15°C
in winter and plenty of shade in summer. When camellias are grown in pots the best
practice is to use a general potting mix containing 500 g of 12-14 month slow release
fertiliser in 200 L of bark and 50 L of sand. Repot every two years. Do not water if the
soil feels moist. Prune after flowering, before spring growth begins. Camellias thrive
well without fertilisers. However, fertilisers, such as well-rotted cow and sheep manure
or blood, can be applied in early spring. Alternatively, ericaceous fertiliser can be
applied once in early spring at a rate half that recommended on the label to
improve growth and flower vigour.
Green tea recipe
Roll freshly picked leaves from C. sinensis (tea plant) between your hands until the
leaves darken and crinkle, allowing the fermentation process to begin. Do not break
the leaves into pieces because the leachate from the broken leaves will give the tea
a bitter taste. Place thin layers of leaves on a tray in the shade for 2-3 days. Then dry
the leaves in an oven at 106°C for 20 minutes to remove all excess water and stop the
fermentation process. Store in an airtight container or use straight away. Brew one
teaspoon of dry leaves for each cup in water that has just begun to produce small
bubbles. Leave for 2-3 minutes. Serve or pour off all liquid to avoid over steeping.
Integrated Garden Management Considerations
Integrated garden management is a set of techniques that are used to control pest
and diseases while benefitting the environment and reducing risks to human health.
Camellia
flower blight
Ciborinia camelliae
Ciborinia camelliae is a fungus that forms capsules
(or sclerotia) of hardened mycelia and petal tissue
that can resist unfavourable environmental conditions.
The pathogen only attacks camellia flowers. Flowers
become brown, and entire intact whorls of petals
(the corolla) separate easily from the receptacle (the
enlarged tip of a stem that bears the floral part)
before falling off the bush.
IGM considerations:
· Grow autumn-flowering species such as C. sasanqua or cultivars that flower early in the season
(mid-late July) before apothecia (the organs that produce spores) are produced by soil-borne sclerotia.
· Burn all infected camellia flowers to kill developing sclerotia.
· Cover the soil under flowering bushes and trim the lower camellia branches to about 0.5 m
above ground to prevent apothecial development from the soil-borne sclerotia.
· Dip camellia blooms into fungicide solutions containing triadimenol plus a few drops of washing
detergent for 5 minutes to prevent cut flowers from becoming infected.
· Use 10 g urea/m2 in February and again in June to reduce the populations of C. camelliae
sclerotia in the soil by stimulating the activity of parasitic micro-organisms.
· If all things fail, apply either of the fungicides, cyproconaxole or fluazinam, to the soil beneath
camellias in early August, and reapply 3-4 weeks later.
Popular ornamental species
C. sasanqua – flowers in autumn and winter
C. japonica and C. reticulata – flower in winter and spring
More than 15 000 camellia cultivars are recognised internationally.
Carrots
Carrots (Daucus carota) are biennial plants that produce and store sugars in single
large roots, called taproots, which are better known to us as carrots.
The earliest carrots were purple or yellow and varied in taste and size.
They were first grown by farmers in the region now known as modern day
Afghanistan. However, the origin and history of the orange carrot are a mystery.
Today scientists and plant breeders are interested in breeding a range of coloured
carrots, but with the familiar carrot aroma and flavour.
Nutritional value of carrots
Food science shows that one medium carrot supplies enough beta-carotene to
meet the body’s needs for vitamin A, a fat-soluble vitamin, for two days. Vitamin A
enhances eyesight, increases cell reproduction, and helps prevent cancer. It also
acts as an antioxidant and an immune system enhancer. Carrots also provide fibre,
calcium, potassium, vitamins C and B, and various other antioxidants.
Steam, stir-fry or microwave carrots to soften the tissue and release vital compounds
bound to cell walls. Avoid over cooking or boiling because heat destroys essential
nutrients contained within the vegetable. Carrot skins and outer leaves contain high
levels of nutrients so avoid peeling and disposing of carrot leaves.
Scientific advice on carrot growing
The most reliable period to sow carrots is July-March in temperate zones, and AugustFebruary in colder zones. Carrots sown in late autumn or winter may go to seed
before they form roots. Research shows that the best carrots are grown on deep, well
drained, aerated, sandy loam soils with good structure. The best soil pH for carrots,
like many other vegetables, is about 6.5. Too much nitrogen promotes leaf growth so
a light dressing of a complete and balanced fertiliser is all that is required.
It is difficult to weed between carrots so prepare the seedbed a few weeks ahead of
sowing to give weeds a chance to germinate and be hoed out. Instructions on
sowing and thinning are provided on seed packets.
Popular carrot cultivars for home gardening
King Chantenay and Early Chantenay, Express Hybrid,
Manchester Table are short-rooted and grow well in
shallow soils.
Baby Carrot matures early, is suitable for sowing
in late autumn and can be grown in pots.
John Evans in the United States produced the largest carrot ever grown. Back in 1998,
he grew a carrot weighing 8.61 kg. It is recorded in the 2003 Guinness Book of
World Records.
Carrot Salad
Method
Mix all ingredients in a bowl and serve immediately.
Ingredients
1 cup grated carrot
¼ cup desiccated coconut
2 tablespoon finely chopped onion
1 tablespoon finely chopped green pepper
½ teaspoon black pepper
½ onion finely chopped
salt, sugar and lemon juice to taste
Lifecycle
Carrot rust fly
Psila rosae
4 generations per year
from eggs laid near carrot
plants: first in SeptemberOctober, second in late
December, third in
February and a partial
fourth generation
by May
Plant damage
Larvae feed on carrot
roots, creating tunnels that
interfere with water
transportation from the
root system
Symptoms
A characteristic rusty or
bronzed appearance on
leaves, wilting, stunting,
and drooping of seedlings
or carrot plants. Roots
have rust-coloured
etching, are deformed
and small
IGM considerations: rotate crops, sow in October and harvest before the peak of third generation flight
activity (mid April-early May), avoid thinning young carrot crops during the peak flights of the successive
generations of adults because a disturbed soil surface will attract egg laying females. Remove and
burn infested crops to prevent the carry-over of pests into the next growing season. Harvest soon after
the carrot taproots develop, and clean up all crop residues to minimise the risk of attack.
Peach-potato aphid Eggs hatch on their overCavariella aegopodii wintering hosts, usually
willow plants. When aphid
colonies become over
crowded, winged female
aphids reproduce without
fertilisation and migrate
towards new host plants
(i.e. carrots) where they
start new colonies in spring
and summer
Extraction of sap from a
single plant by a large
number of aphids.
Additionally, aphids
transmit the motley dwarf
virus, which can stunt
carrot growth at a very
early stage, causing leaf
stalks to twist and foliage
to turn yellow or red
Yellowing, wilting, leaf
curling/galling, puckering,
distortion of new growth,
stunted shoot growth and,
in serious cases, plants
wither and eventually die
IGM considerations: sow late in the season (autumn or winter) to avoid migration flights, conserve
natural predators such as lady beetles and spiders, avoid using pesticides unless they are absolutely
necessary because repeated application of broad-spectrum pesticides can kill beneficial insects as
well as pests. Aphids can recover faster than other insects after insecticide treatment, which can cause
an imbalance between beneficial insects and aphids, worsening the problem. If symptoms cover 25%
of the plant’s surface, take some action, but if the damage is greater than 50% or more it is already
too late - the time for action has already passed.
Stone fruit
Peaches, plums, cherries, nectarines, and apricots, known as ‘stone fruit’ or
‘summerfruit’, are grown in home gardens throughout New Zealand. The name
‘stone fruit’ refers to the single stone-like seed inside these fruits.
Nutritional benefits of eating stone fruits
Needless to say, there is overwhelming evidence that stone fruits are highly nutritious. They
are low in calories, high in fibre, and rich in vitamins A and C and trace elements.
Fibre is divided into two classes: insoluble and soluble. Insoluble fibres provide faecal
bulk and help food move faster through the gut, while soluble fibres can reduce
blood cholesterol. Vitamin C helps the body to absorb iron, boosts the immune
system, and assists in growth and repair. Apricots and peaches are high in betacarotene (vitamin A), which helps eyesight, improves the immune system, and
promotes healthy skin and bone. Plums contain moderate levels of vitamin E, an
antioxidant that helps defend body cells against damage, while cherries also have
high antioxidant properties.
Scrummy Stone Fruit Dessert Dressing
Remove stones and slice ripe stone fruits of your choice, mix with cream cheese, fresh
or whipped cream and flavour with orange juice, thinly sliced orange peel and sugar.
Serve with fresh fruit, ice cream, pancake or any other dessert.
Stone fruit crops
Varieties suited for
North Island, NZ
Varieties suited for
South Island, NZ
Apricots
Sundrop, Royal Rosa,Trevatt, Judge Turner
Sundrop, Moorpark,
Roxburgh Red
Peaches
Prunus persica (L.) Batsch
Redhaven, Golden Queen, Spring Crest
Spring Lady, Yumyeong
Flamecrest, Redhaven
Nectarines
Spring Red, Armredark, Snow Queen
Fantasia, Redgold
Sweet Cherries
Stella, Early Rivers, Dawson, Bing
Stella, Dawson, Rainier,
Burlatt
Prunus armeniaca L.
Prunus persica (L.) Batsch var.
nucipersica (Suckow) Schneid
Prunus avium L.
European plums and prunes Coe's Golden Drop, Stanley, Italian, Richards Greengage, Italian,
Prunus domestica L. and
Early Italian, Greengage
Richards Early Italian,
Prunus insititia L.
Coe's Golden Drop,
Stanley, Cacak Fruitful,
Damson
Site selection
Stone fruits grow well in areas of New Zealand with cold winters and hot dry summers.
They grow best in naturally fertile and free-draining soils, provided the fruit can
escape spring frosts and be irrigated.
Peaches, nectarines and some Japanese plums grow well at sea level. However,
apricots, European plums, and sweet cherries tend to produce light crops and
excessive vegetative growth when grown in climates where there is inadequate
winter chilling.
Apricots need to be planted on elevated land, not only for soil drainage but also for
air drainage. If planted on elevated ground, they not only avoid extreme cold
conditions, but both the foliage and fruit dry out faster, thus avoiding some of the
more damaging diseases.
Important disease of stone fruits in New Zealand
Bacterial blast
Exposure to cold in autumn and early spring. Damage leads to oozing
of amber-coloured gum from canker and black scabs on fruit
Management recommendation:
Apply copper programme - 2 sprays about 3 weeks apart in autumn
when leaf fall begins, and then continue with 2 sprays in spring.
Prune out dead wood.
Note: If possible, protect blossom and small green fruit from spring
frosts.
Bacterial spot
Symptoms develop quickly under warm wet conditions from November
onwards, but the problem begins with a frost that occurs between
flowering and shuck fall, and is followed by warm wet weather.
Management recommendation:
Avoid overhead sprinkling during the day in summer
Apply copper programme in autumn
Brown rot
Severe in seasons and regions where there is high rainfall, combined
with warm and wet conditions, either during flowering or close to
harvest.
Management recommendation:
Remove all remaining fruit from the tree (healthy or otherwise)
Remove or mulch prunings
Peach leaf curl
Occurs on peaches and nectarines but rarely on flowering peaches
Management recommendation:
Apply copper when first signs of leaf development begin (just before
flowering)
Remove primary red-leaf infections before they reach the "white bloom
stage".
Causes shoot, limb and even
tree death and spotting on fruit
Causes flat black spots on fruit
and cracking of bark
Fungus infection that causes
major fruit losses at harvest, both
on the tree and postharvest
Fungus infection that causes
reddening and distortion of
leaves of peaches and
nectarines