Potatoes… - Bayer CropScience

“Wanted poster“
for the Colorado potato beetle (Leptinotarsa decemlineata):
The Colorado potato beetle overwinters in soil. It is 10 to 12 mm in length, with
orange to yellow and black stripes. Infestation can occur as soon as potato plants
emerge, with the beetle eating the young leaves. After mating, the female beetle
lays orange-coloured eggs in groups of 12 to 25 on the leaf under-surface.
The 15 mm-long, reddish-coloured larvae emerge and feed on the potato leaves.
Eventually, they form pupae in the soil from which young adult beetles emerge
after about 14 days.
In cooler climates, there is only one generation of beetles per year. But under
optimal temperatures (25 to 33 degrees Celsius), up to four generations can occur.
The Colorado potato beetle is easy to recognise by virtue of its size and colouration.
When the potato plant is shaken, the beetles allow themselves to fall off. In
this way, otherwise hidden specimens can be seen.
The beetle was first
recognised in North
America at the
beginning of the 19th
century and has
become widely distributed
in the meanwhile.
During the 20th
century, it made its
way throughout
Europe towards the
East and has now
reached China.
“Wanted poster“
for the green peach aphid
(Myzus persicae):
The eggs overwinter on peach trees.
The larvae emerge in the spring:
Then, over a period of several weeks,
they develop into winged or wingless
adults. The winged aphids fly to their
summer hosts, including the potato.
They feed on the plant, but cause
more damage by transferring viruses
(including the persistent leaf roll
virus).
The aphid has an oval body, 1.2 to
2.1 mm long, which is light to dark
green, pink or reddish-coloured.
Winged specimens have a characteristic
black mark on the abdomen.
Between 10 and 25 generations can
occur per year.
Originating in Asia, this aphid is now
found in all areas of potato cultivation
around the world.
Alternating active
substance classes
Over the years, a number of crop protection
products have been used successfully
against Colorado potato beetle, aphids and
other pests, mainly from the organophosphate
and pyrethroid classes of active substance.
Now, innovative products from the
chloronicotinyl (CNI) class are becoming
increasingly predominant. Bayer products
such as Calypso ® and Biscaya (thiacloprid),
Confidor ® (imidacloprid) and Monceren ®
G (imidacloprid plus the fungicide pencycuron)
belong to this class. Their major
advantage compared with the organophosphates:
they are both user- and environment-friendlier.
Moreover, hardly any
resistance to them has arisen in the pest
populations that confront potato crops. To
provide over all protection during the early
growth phases, Monceren ® G, with the
systemic active substance imidacloprid, is
sprayed onto potatoes at the time of sowing
to protect them for several weeks against
aphids and early infestation by Colorado
potato beetle. However, the pests can
appear throughout the entire growing
period. If they go on to reach damage
threshold levels, Biscaya is available to the
farmer as a novel, effective insecticide for
foliar application.
Biscaya – with an
innovative formulation
“Biscaya was introduced into practice with
great success in 2007“, reports Julia van
Bömmel (Product Manager for Biscaya).
“With its active substance thiacloprid, it is
making a significant contribution to offsetting
the Colorado potato beetle resistance
threat.“ This will bring a lot of relief to
growers in countries such as Germany and
Poland, who are increasingly affected by
the resistance problem.
The new Biscaya also offers further advantages:
a glance at the product description
will show that Biscaya has a
favourable profile with regard to beneficial
insects and the environment. The product’s
safety to bees means that it is also suited
for use during flowering-time.
24 COURIER 1/08