Download Pest Information for European Union Horticultural Exports

A GUIDE TO COMPLIANCE WITH THE EUROPEAN UNION’S
PHYTOSANITARY REQUIREMENTS ON HARMFUL ORGANISMS
INTRODUCTION
The European Union (EU) remains one of Kenya’s major markets for flowers, vegetables and
fruits. This is despite the challenges faced due to increased incidences of interceptions due to
presence of harmful organisms and exceedance of the pesticide maximum residue levels. The
pests banned in the EU are listed in the Council Directive 2000/29/EC of 8 May 2000 Annex I
and II after extensive pest risk analysis is carried out.
COUNCIL DIRECTIVE 2000/29/EC OF 8 MAY 2000
Council Directive 2000/29/EC of 8 May 2000 lays down measures designed to protect EU
member states against the introduction of organisms harmful to plants and plant products from
other member states or third countries. This Directive also lays down measures designed to
protect Member States against the spread of harmful organisms within the EU.
The Directive covers living plants and living parts of plants, including seeds. Living parts of
plants are: Fruit and vegetables that have not been deep frozen
 Tubers, corms, bulbs, rhizomes
 Cut flowers
 Cut trees and branches with foliage
 Leaves
 Live pollen
 Grafts and any other part of a plant
"Harmful organisms" as defined by the Directive means pests of plants or of plant products
which belong to the animal or plant kingdoms, or which are pathogens. This definition covers in
particular insects and mites, bacteria, fungi, viruses and parasite plants. Annexes I and II list the
harmful organisms banned in the EU, either altogether or when they are on certain plants or
plant products. Annex III lists plants and plant products that must not be imported from certain
countries.
Some of the pests in Annex I and II are:1. Tephritidae (non-European) fruit fly
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Adult Fruit Flies – Bactrocera invadens (left); Dacus bivittatus (centre) and Bactrocera cucurbitae(right)
There are about 950 species and 150 genera of Fruit Fly (Tephritidae) known in Africa. Most of
these species form a natural part of Africa’s varied biodiversity and live on wild flowers and
fruits. The two main species that are significant pests on cultivated commercially grown fruit
crops belong to 2 genera: 95 species of Ceratitis and 195 species of Dacus. The other species to
note are Trirhithrum (Coffee Fruit Flies) which are closely related to Ceratitis and Bactrocera
which are close relatives of Dacus.
The main interceptions within the EU of fruit flies originating from Kenya are of the species
Dacus with Bactrocera sp also being found.
1.1 Host plants
 Main: Mango, guava, custard apple
 Others: cashew nuts, pineapples, capsicums, pawpaw, watermelon, citrus fruits,
cucumber, pumpkins, loquat, karella, banana, marula, apple, avocado, tomato, coffee,
Black nightshade, etc.
1.2 Pest biology
Eggs are laid below the skin of the fruit in groups of 3 to 7 as more larvae than this will have
insufficient nutrients to survive to pupation. The eggs hatch within 1 - 2 days with the larvae
feeding for 5 - 6 days during the summer and slightly longer periods during the cooler periods
of the year. The larvae exit the host plant and pupate in the soil where the adults hatch in 2 – 4
weeks depending on temperature.
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1.3 Symptoms of Fruit fly damage
Oviposition punctures are the normal evidence of damage. On Cucurbits this may show as one
or two oviposition punctures but on Mango there are normally multiple punctures as seen in
the pictures below.
Fruit Fly infestation of Cucurbit
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Multiple oviposition marks on Mango and larvae
Mango with oviposition punctures and ooze from some punctures and
Live Fruit Fly larvae seen in an infected Mango
1.4 Management and control of fruit flies
Control of the pest in the production areas is very difficult due to the wide range of natural
host plants and fruit available. The following IPM package is recommended:
i. Fruit fly Monitoring system:
This is largely carried out by having traps set in areas of infestation. This may be complemented
with host fruit surveys and subsequent incubation of the fruits. Regular scouting should be done
to determine thresholds of the pest in the crop and to revise control measures appropriately.
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Trap used for fruit fly monitoring
ii. Orchard sanitation
This involves the removal and destruction of fallen fruits because they may harbour larvae that
could form a next generation. This is done by burning, deep burrowing (at least 0.5m below the
surface) or putting the fruits in dark-coloured plastic bags and placing them in the sun (so that
the inside temperature rises and kills the larvae); raking or disturbing the soil below the fruit
trees and keeping the ground mulch free will expose the puparia, leading to desiccation or
predation by other organisms. Also, removal and destruction of old stands that would serve as
sources of pest multiplication should be undertaken.
(Top left) Mango wastes after harvesting in an orchard; (Top right) Waste
disposal pit dug in the orchard (Above left) Dark-coloured plastic bags
(Bottom right); Boiling of fruit wastes
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iii. Male population suppression techniques
The control strategy uses high density trapping stations consisting of a male attractant
combined with insecticide. This would be effective in reducing the population to a very low
level if carried out on a large scale. Bait station devices that combine a lure or bait with
toxicant that attracts and kills fruit flies without retaining them in the device may also be used.
(Left) Fruit flies attracted to a trap before they are killed; (right)A block laced with
insecticides and attractants used as a bait station (right)
iv. Chemical control
May use bait sprays consisting a suitable insecticide mixed with protein bait or cover sprays at
least three weeks prior to harvest. Bait sprays entail the use of food baits (hydrolyzed proteins
or their ammonium mimics) combined with a killing agent. This method targets adult flies mainly
females and aims at attracting and killing them before they infest fruits (lay eggs into the fruits).
For cover sprays, assess the risk of fruit fly from weekly pheromone trap counts. Focus on
orchards with high counts but ensure that a preventative programme is in place all over the
farm. If fruit fly numbers are above the threshold of 2 per trap/week; one spray of products like
spinosad/imidacloprid should be effected.
v. Mechanical fruit protection:
Involves bagging/sleeving/wrapping individual fruits with paper when the fruits are at egg size
stage.
An orchard with bagged fruits
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Furthermore, pack houses should have well trained quality inspectors working on their packing
lines to ensure all suspect fruit is detected and removed from consignments destined for the
export market.
2. SPODOPTERA SPECIES
There are a number of moths of the genus Spodoptera which are recognised as quarantine pests in the
EU Member States but Spodoptera littoralis (The Mediterranean Climbing Cutworm) which is present in
the Mediterranean region of Europe and in Africa is of concern to Kenya. S. littoralis is a destructive pest
of agricultural crops both within the sub-tropical and tropical regions and the moth has the potential to
be a very serious pest of glasshouse crops in northern Europe. The larval stages feed on a very wide
range of ornamental and edible crop plants. Many of the populations that have tested have been found
to be resistant to pesticides and are very difficult to control.
S. littoralis adult
2.1 Host plants
S. littoralis is totally polyphagous. The host range of plants covers over 40 families containing at
least 87 species of economic importance. Among the main crop species attacked are Colocasia
esculenta, cotton, flax, groundnuts, jute, lucerne, maize, rice, soya beans, tea, tobacco,
vegetables (aubergines, brassica, capsicum, cucurbit vegetables, phaseolus, potatoes, sweet
potatoes etc. Other hosts include ornamentals, wild plants, weeds and shade trees.
2.2 Pest biology.
About 2 – 5 days after the female emerges, she lays 1000 – 2000 eggs. These are laid in egg
masses of 100 - 300, on the lower leaves of plants and other surfaces. The eggs are whitishyellow and covered with a mass of brown hairs from the female giving a ‘felt’ like appearance.
The eggs hatch in about 4 days in warm conditions. The larvae pass through six instars The
young larvae (first to third instar) feed in groups on the underside of the leaves of the host
plants, leaving the opposite epidermis of the leaf intact. Later, the (4th to 6th instar) larvae
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disperse and spend the day in the ground under the host plant, feeding at night and early in the
morning. The pupal period is spent in earthen cells in the soil and lasts about 11-13 days at
25°C.
Spodoptera littoralis 1st instar larva
2.3 Symptoms of Spodoptera littoralis damage
On most crops, damage arises from extensive feeding by larvae, leading to complete
stripping of the plants.
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Spodoptera damage on leaves
i.
a. Management of Spodoptera
IPM: Integrated Pest Management techniques, favouring beneficial arthropods, have
been successfully applied against Spodoptera species. These involve hand collection of
egg masses, use of microbial pesticides and insect growth regulators and slowrelease pheromone formulations for mating disruption. These measures are
combined with, relatively few applications of conventional insecticides as necessary.
Pheromones have also been used for mass trapping using a lure and kill strategy.
ii. Chemical control: Chemicals used against species of Spodoptera include synthetic
pyrethroids and insect growth regulators. There is also some interest in the use of
various antifeedant compounds or extracts, and in natural products, such as
azadirachtin and neem extracts.
iii. Biological control: Parasitoids (braconids, encyrtids, tachinids and ichneumonids) and
predators have been extensively documented. A nuclear polyhedrosis virus and
parasitic nematodes such as Neoaplectana carpocapsae have been evaluated and found
effective. Treatment with Bacillus thuringiensis has been used, but only some strains
are effective as S. littoralis is resistant to many strains.
iv. Cultural: Sanitation - removal of all the dry leaves /debris and weeds that can be
alternative hosts at production facilities; use of insect screens on side curtains/vents
to prevent entry of moths for green house production facilities; appropriately
disposing all the infected materials.
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v. Monitoring sytems: using pheromone traps and/or scouting techniques to act as an
early warning and rapid response whenever infestations occur.
3. WHITE FLIES Bemisia tabaci Genn. (non-European populations)
3.1 Pest Biology
Eggs are laid usually in circular groups, on the undersides of leaves, with the broad end touching the
surface and the long axis perpendicular to the leaf. Eggs are whitish in colour when first laid, but
gradually turn brown. Each female lays up to 160 eggs. Hatching occurs after 5-9 days at 30°C depending
on host species, temperature and humidity.
On hatching, the first instar or crawler is flat, oval and scale-like, and is the only mobile larval stage. It
moves to a suitable feeding location on the lower leaf surface where it moults and becomes sessile
throughout the remaining nymphal stages. The first three nymphal stages last 2-4 days each (depending
on temperature). The fourth nymphal stage is termed the puparium, and is approximately 0.7 mm long.
Pupation lasts for about 6 days and within the latter period, the metamorphosis to adult occurs.
The adult emerges through a 'T'-shaped rupture in the puparium and expands its wings before
powdering itself with wax from glands on the abdomen. Copulation begins 12-20 hours after emergence
and takes place several times throughout the life of the adult. A female may live for 60 days, although the
life of the male is generally much shorter, ranging between 9 to 17 days. Some 11 to 15 generations can
occur within one year.
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3.2 Hosts
Bemisia is widely polyphagous, feeding on over 500 species of plants in 74 families. Its hosts
include vegetable, field and ornamental crops. Bemisia is a major pest of tomato, peppers,
squash, cucumber, beans, eggplant, watermelon, cabbage, potato, peanut, soybean ornamentals
and cotton.
3.3 Damage Symptoms
B. tabaci can acquire and transmit a range of plant viruses which produce a variety of different symptoms
on susceptible plant species. Although plants can become infected from migratory feeding of B. tabaci,
plants infected with B. tabaci-transmitted viruses are often indicative of B. tabaci colonization.
Infected plants could exhibit any one or a combination of the following symptoms: vein yellowing, intervein yellowing, leaf yellowing, yellow blotching of leaves, yellow mosaic of leaves, leaf curling, leaf
crumpling, leaf vein thickening, leaf enations, leaf cupping, stem twisting and plant stunting.
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Pepper infected with Pepper golden mosaic virus (left); Squash infected with Squash
leaf curl virus (right)
White fly on leaves
Tomato foliage showing characteristic yellowing and
l curling associated with infection by Bemisiavectored tomato yellow leaf curl virus
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Whitefly infestation
3.4 Management of the White Fly
Until recently, B. tabaci was readily controlled with insecticides in field and glasshouse
situations. However, problems with its effective control on many crops are now being
experienced worldwide due to insecticide resistance. It appears that no single control
treatment can be used on a long-term basis against this pest, and that the integration of a
number of different control agents needs implementing for an effective level of control.
IPM appears to offer the best option for controlling B. tabaci without causing contamination of
the environment: beneficial insects are used alongside chemicals that offer a high level of
selectivity such as insect growth regulators, the use of biological control agents such as Encarsia
formosa and Verticillium lecanii, use of yellow sticky traps for mass trapping, instituting a pest
monitoring system, cultural methods of field sanitation, among others.
i. Whitefly monitoring system:
There should be an adequate number of scouts dedicated to the production blocks, regularly
trained and allocated an area they can cover effectively. The scouting should be done regularly
and the resulting reports used by the management to make pest management decisions. Yellow
sticky traps may be used as a monitoring device to supplement the work of the scouts.
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ii. Farm sanitation
This involves the removal of all weeds inside and outside the production areas which would
otherwise act as alternate hosts for the pests. The production area should also be free from
mulch or any dirt as the pupal leaf miner stages will find an appropriate habitat in this.
iii. Insect population suppression techniques
A network of yellow sticky traps should be adequately installed within the production blocks to
reduce the populations of insects to low levels.
iv. Mechanical control
Where appropriate, some crops may be produced within an insect screen tunnel or a green
house. In the case of a green house, insect netting should be used to cover all ventilations to
eliminate entry of insects. Also, green house entrances should have double doors to minimize
the chances of insect entry once the operators gain entry and exit into and from the green
house.
v. Chemical control
Whenever pest population levels increase within the production facility, appropriate chemical
cover sprays should be applied. However, safe use of chemicals should be observed and the
produce regularly analyzed for chemical residues.
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