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Progress in the use of predatory mites for pest
control Maurice Sabelis, Arne Janssen, Iza Lesna & Karen Muñoz-Cárdenas
November 16th, 2014 International Congress of Entomology
Portland, USA
Recent research on biological control of plant-feeding arthropods with predatory mites has focused on interactions in more complex food webs. Using examples from research conducted at the University of Amsterdam and collaborating institutions, I will focus on:
• The use of alternative food and prey
• Predatory mites for control of belowground pests
• The role of plant structures
Alternative food
?
• Only first-instar larvae of thrips and eggs and crawlers of whiteflies are vulnerable to predatory mites.
• Even when pests have a short vulnerable stage, control can be obtained when densities of predators are high.
• Densities of predators can be increased through the addition of alternative food.
3
num
ber /
pla
nt
num
ber /
pla
nt
predators (active stages)
4 5 6 7 8 9 10 11 12 13 14 15 16
16
1
10
100
1000
4 5 6 7 8 9 10 11 12 13 14 15
pollen
no pollen
thrips (larvae)
1
10
100
1000
no pollen
pollen
Time (weeks)
Iphiseius degenerans
Frankliniella occidentalis
van Rijn et al. 2002 Ecology 83: 2664 4
0
2
4
6
8
10
0 20 40 60
ln (B
emis
ia ta
baci
)
Time [days]
control
+ predators
+ predators + pollen
14009
563
56
Nomikou et al. 2010. Biocontr 55: 253
Bemisia tabaci
Amblyseius swirskii
5
+
+ Pollen
Alternative food
Here you see apparent competition. The densities of whiteflies are lower in the presence of thrips, both prey are attacked by the same predatory mite (Amblyseius swirskii).
Messelink et al. 2008. Bio. Ctrl 44: 372
0
2000
4000
6000
8000
3 4 5 6 7 8 9 10
Den
sity
of
Bem
isia
taba
ci
Time [weeks]
Bemisia tabaci
Amblyseius swirskii Alternative prey
6
+
Frankliniella occidentalis
Belowground pests Hypoaspis aculeifer controls bulb mites in lily
Lily bulb’s propagation phase - the most severe damage
Hypoaspis aculeifer Bulb mites
Lesna et al. 1996. J appl. ecology 33:369 7
•Y-axes express numbers as Y + 1 on a log scale • Vertical bars represent standard errors of log-transformed numbers (SE)
6 5 4 3 2 1 0
mite
s per
bul
b
1
10
100
1000
10000
6 5 4 3 2 1 0
1
10
100
1000
0.1
time (weeks) time (weeks)
predators
predators absent (2 initial prey densities)
predators present
prey prey
Propagation phase
Lesna et al. 1996. J appl. ecology 33:369 8
mite
s per
bul
b
predators
16 14 12 10 8 6 4 2 0
1000
100
10
1
time (weeks)
prey in presence of predators
prey in absence of predators
Lily fields Hypoaspis aculeifer Bulb mites
Lesna et al. 1996. J appl. ecology 33:369 9
Plant structures Typhlodromalus aripo inhabiting the apex in cassava plants
Apex provides T. aripo with protection against weather, UV and intraguild predation, and possibly also provides food (phloem exudates). BUT time spent in apex distracts T. aripo from preying on the cassava green spider mite. ? Onzo, Sabelis & Hanna (2003) Oikos 101:59 10
Diurnal movements of T. aripo between apex and leaves within cassava plants
Onzo, Sabelis & Hanna (2003) Oikos 101:59
0
10
20
30
40
12 h 16 h 20 h 00 h 04 h 08 h
Num
ber
of p
reda
tors
per apex
per leaf
11
Reduction of M. tanajoa in cassava fields
T. aripo had much larger effect on the pest than the native A. manihoti or E. fustis. Largest reduction of cassava green mites by T. aripo plus A. manihoti
Onzo, Hanna & Sabelis 2014. Exp Appl Acarol 62:293
0
10
20
30
40
50
A. Manihoti fields E. fustis fields
% M
. tan
ajoa
redu
ctio
n both T. aripo Leaf inhabiting presators
12
Neoseiulus cucumeris controls Aceria tulipae on stored tulip bulbs in cardboard boxes, but not in open trays.
Predatory Mites Control ?
?
Lesna, Conijn & Sabelis 2004. Phytophaga, XIV: 285
Neoseiulus cucumeris
Aceria tulipae
Plant structures Dry bulb mites seek refuge in tulip bulbs
13
• Dry bulb mites (Aceria tulipae) destroy tulip bulbs from inside, and predators have no access to bulb interior
• Infested tulip bulbs produce ethylene, which is a plant hormone released upon herbivore attack.
• Ethylene increases space between inner bulb scales and attract predatory mites (Aratchige et al. 2004)
• Predatory mites then gain access to the interior of the bulb
• Predatory mites eliminate dry bulb mites in and on the bulb
Rationale: Viability of bulbs declines after exposure to ethylene, but if the alternative is to be destroyed from inside, ethylene is indirectly beneficial by promoting predation
A hypothesis on below-ground plant defence in tulip bulbs
Lesna, Conijn & Sabelis 2004. Phytophaga, XIV: 285
Aceria tulipae
Neoseiulus cucumeris
14
Prey inside tulip bulbs
control
Ethylene exposure
14
100000
1
10
100
1000
10000
0 2 4 6 8 10 12 14
1
10
100
1000
10000
100000
0 2 4 6 8 10 12
time (weeks)
mite
s per
bul
b
predators present
1
10
100
1000
10000
100000
0 2 4 6 8 10 12 14
predators absent
1
10
100
1000
10000
100000
0 2 4 6 8 10 12 14
time (weeks)
Lesna, Conijn & Sabelis 2004. Phytophaga, XIV: 285 15
16
However, treatment with ethylene has negative effects on flower development, so is not a feasible option for control of the dry bulb mite. So we need smaller mites, which can enter a closed bulb. A coconut mite offers a solution:
Neoseiulus paspalivorus Minimum diameter: c. 60 mm
Neoseiulus paspalivorus Minimum diameter: c. 60 mm
Lesna et al. 2014. Exp. Appl. Acarol. 63: 189–204
Better control of dry bulb mites with the small predatory mites from coconut.
control N. cucumeris N. paspalivorus
Lesna et al. 2014. Exp. Appl. Acarol. 63: 189–204
Conclusions
• Biological control of plant-feeding arthropods with predatory
mites is possible even in more complex food webs.
• The use of alternative food and prey helps in reducing pest densities, also of pests with short vulnerable stages.
• Predatory mites can be used to control belowground pests.
• Plant structures can provide refuges to predators but can also provide shelter for pests. In the last case, plants have to make the structures accessible to predators.
Thanks for your attention!
