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IRRI Saturday Seminar
August 4, 1973
Prospects and Problems of Integrated
Pest Control in Multiple Cropping ..
R. S. Raros
Introduction
The one important biological feature of multiple cropping
is its built-in diversity: firstly, of the flora and secondly, of
the fauna. Whether agricultural development chooses to ignore or
to harness the known benefits of biological diversity will deter-
mine the biology of wide areas of cultivated ecosystems. In the
area of pest control the choice may mean maximum or minimum' fre-
quency and intensity of resource inputs to the system. Consider-
ing both the biological and technological aspects of agriculture
in Southeast Asia, the following may be worth noting: 1) that the
region has an inherently rich and diverse flora and fauna, but
2) the farmer is, on the .aetage, very. poor;. he lacks the techno-
logical resources .on..which greatly.depend the sophistication and
success-of his western counterpart.
S .In this setting, one can not help but agree with Conway
and Romm's (1972)1/statement:
"Theoretically, diversified systems....can be
designed which control pests and diseases more by
their internal dynamics than by the chemical: and a .:
mechanical means upon which specialized systems must :
depend."
This paper presents recent results of studies designed to
demonstrate the feasibility and potential of several approaches
to integrated pest control (management) in cultivated agro-ecosystems.
Possible strategies are suggested'on the basis of these findings.
The Program
Figure 1 illustrates the guidelines of research emphases:
I. Biotic Interactions to encourage-:beneficial inter-
actions and promote biological stability.
1/ Conway, G. and J. Romm. 1972. Ecology and Resource'Deve-
lopment in Southeast Asia. A Report to the Ford Foundation.
Bangkok, Thailand. 54 pp.
-2-
II. Nutrient Recycling to further improve biotic inter-
actions, soil structure and related properties, and plant nutrition.
III. Modern Agricultural Techniques -,to minimize the dis-
ruptive influence of these techniques on the functioning of the
system.
These objectives emphasize the unity of a cultivated farm
and the need for unifying interdisciplinary approaches.
Recent Studies .
I. Biotic interactions; corn-peanut and..cabbage-tomato
intercropping. Corn-peanut cropping combination is one of the
more widespread combinations in .the region. Why it persists is of
-interest because the reasons.may provide better insight into the
development of more productive cropping systems..
Quiterecently. (IRRI Annual Report, 1972), we reported the
discovery that corn, intercropped with peanut, was less infested
.by the corn borer,. Ostrinia furnacalis Guence. Reduced infestation
by the diamond-back moth, JPlutella xylostella L., on cabbage inter-
cropped in the tomatoes was.also reported at the aame' time. These
benefits were consistently demonstrated in subsequent trials
(Tables .1 to 3) in which the. influences of.change in field hue and
predation by spiders on the corn borer's performance was evaluated.
The data show the following:
1. That,.the borer moths have less. preference for a solid
green background than thoae with brownish hue, especially during
the early stages .of plant growth..
2. That movement of predatory spiders is in continuous
flux.and that spiders. show. no. apparent preference between corn-
peanut and corn alone stands(Fig, 5): ...
3. That artificial introduction of spiders to both stands
decrease but do not erase previously observed difference in borer
infestation between the stands. It seems that predation is more
efficient in a corn-peant stand than in one with corn alone, and
4. That the application of a highly toxic broad spectrum
insecticide completely nullifies the. pest.contrQp advantage de-
rived from corn-peanut intercropping..:. ,,.
The role of predation by spiders in monocultrre-stands
involving upland .(Fig. 2) and lod la rice. (Fig. .3) was, also
.', : ", ". ;i .. .. :. ' ? ; i :" - : i
-3-
further examined; The data show that the desired balance between
predator and pest occurs too late. It is suggested that predation
may generate an impact if encouraged or introduced early, perhaps
before 30 days -after transplanting.
II. Crop litter turnover.
Interest in crop litter is generated by the following ad-
vantages:
1. Macro and microarthropods associated with the break-
down, decomposition and nutrient cycling contributes to the fauna
in the system.
2. 'Processes involved in natural nutrient flow improve
various soil properties and Chabrcteristics which, with intensive
land use may degenerate rapidly, and
3. A major energy drain from the system is appropriately
plugged.
The numbers of dominant macroarthropods associated with
corn, mung and peanut litters under the canopy of growing corn
plants are shown in Table 4- The activities of stratiomyiid larvae
constitute the major fragmentation process, and together with va-
rious other faunal life forms,'may encourage the abundance of
predatory groups like staphylinid beetles, dermapterans and spiders.
It is also of interest to note that encouragement of-macroarthropodi
abundance may be obtained with molasses treatment of litter although
this would vary with the type of crop litter.
-Table 5 shows the population 6f fungi and bacteria on the
litter and in the soil immediately underneath at 0.5 and 5.l0 cm
deep. Microbial abundance'varies'with type of litter, state of
decomposition and faunal succession in litter. For rice litter
buried under corn and in which fragmentation activities of macro-
arthropods are eliminated, the dominant "decomposers" are constituted
initially by Collembola (Fig. 47.- and later.by saprophagous acarines
mainly of the families Pyemotidae and Uropodidae and suborder Oribatei
(Fig. 41-. There are also present numerous predatory mite species
including members of the families Rhodacaridae, Digamasellidae and
Eupodidae among the dominant ones (Fig. 4c).
III. Agricultural technology
Technological innovations to control pests are a major
consideration in any farm production program. While the impact
of technology, specifically pesticide technology, is recognized their
-4-
unbridled usages have already elicited the expected response of
a biological system to the destruction of its structure.- The
p6tintis, how to bridge biological niceties and technological com-
petence without creating biological absurdities.
Contributions towards judicious use of pesticides can be
made with the following research emphases:
1. Insecticidal screening for chemicals with low toxicity
to naturally existing biotic control agents like spiders (Table 6).
2. Re-evaluation of application dosages to determine mi-
nimal effective rates according to major groups of pest species
and crop types. For example, Table 7 demonstrates that chlorpy-
rifos may be applied at rates lower than the manufacturer-'s-recom-
mendation but still afford protection against insect pests of mung.
3. Timing of insecticidal protection based on the least
tolerant stages of crop growth, that is, stages in which tolerance,
recovery or regeneration rates from insect damage are least. For
instance, the efficiency for the use of Dipel to protect cabbage
against the diamond-back moth is low during early and late growth
stages because of the plant's capacity to recover when fed upon in
the early growth stages and its tolerance to feeding damages in
later growth stages (Table 8). Or, in case of protection for mung
and bush sitao, Table 9 shows that little advantage is gained from
the application of pesticides in the last-half of the growth of
the plants.
Conclusions
The farm is a living system. Left undisturbed and given
time, its components attain stable relationships amongst each other
and become as productive as the physical environment permits. The
exploitation of this productivity through agriculture inevitably
results, however, into certain degrees of disturbances which render
the system less stable and less efficient. Agriculture, being in-
herently disruptive, must therefore provide compensatory technology
to keep the system "alive", efficient, and productive. Unfortunately,
pest control technology has evolved loopsidedly towards non-biological
compensations that require not only vast capital investments but,
more importantly, may render the system totally dependent on said
technology. While the impact of this technologyto food production
is recognized, the need for a more biological perspective in de-
signing pest control strategies has become increasingly evident.
The studies presented here suggest that pest control technology can
be managed to capitalize on natural interactions and, therefore,
become less disruptive of the agro-ecosystem's structure and func-
tional organization than prevailing techniques.
Table 1. Influence of field hue on corn borer oviposition in corn
alone and corn-peanut cropping systems. N8 IRRI, June-August, 1973.-a
Cropping Days after seeding .. ::
systems 29 35 42 51
No cover..
Corn alone :13 16 58 42
Corn-peanut 6 2 .. :.26 42
% reduction 53.8 87.5 55.2 0
Brown cover -on soil and/or peanut- :
Corn alone 14 27 44 ;: 38
Corn-peanut 5 21 38 30
7 reduction .: 64.3 22.2 :.-13.6- 2::21.0
-.. Green-brown co ver' on soil and 'or' peanut"-"
Corn alone l,27. 49- 50
Corn-peanut -;:: 22 43 51
% reduction 45.4 18.5 12.2 0
Green cover on soil and/or peanut
Corn alone 8 46 46 51
Corn-peanut 6 19 42 45
% reduction 25.0 58.7 9.5 11.8
a/ Planted June 11. Values are corn borer egg masses per 100
plants based on observation of 50 plants per 60 sq.m treat-
ment plots, average of 2 replications.
Table 2. Number of corn borer egg masses before (35 DAS) and after
.(40 DAS). spider releases Iin- corn and- corn-peanut crops treated--with
Guaathion or.Dipel. :NN6 IRI, June-July 1973. 'i .
Number of egg masses/100 corn plants"
Treatments 35 DAS 40 DAS
Corn Corn- Diffb/ Corn Corn- Diff.y
S alone peanut alone peanut
A. Gusathion-treated,.
Spiders released
B. No pesticides,
Spiders not released
C. No pesticides,
Spiders released
C. Dipel-treated,
20 19
20
- 5.0 41 51
.9 -54O--- *55-' 29
18 10 -44.4 31 22
24.4
-47.3
-29.0
SSpiders released 13 5 -61.5 44 33 -25.0
a/ Planted June 13. Spiders released 20-22 July (37-39 DAS),
one Lycosa pseudoannulata adult per 3 corn plants.
b/ % difference due to peanut
: .
~ : ;..: ;
: ...
Table 3. Incidence of diamond-back moath in cabbage-tomato inter-
cropping. UPCA, January-Marcha 1973.A
Days after Cabbage rows between tomato rows
transplanting 1 2 3 4 5
Number
14
29
31
37
39
43
46
47
51
52
53
56
59
60
64
Total
17
8
25
S 8
17
17
0
8
33
25
0
50
25
25
50
308
of adults/100 plants
S13
13
25
33
25
17
. 33.
42
33
25
50
142
133
108.
58
750
11
39
44
89
30
50
53
55
133
131
181
236
184
161
100
1497
11
46
81
129
50
69
77
77
208
161
154
244
192
179
144
1822
18
52
70
142
74
88.
77
97
207
155
180
185
200
184
105
1834
Number of eggs/plant
14
29
31
39
46
52
59
Total
13.67
3.67
6.67
3.42
3.92
6.50
8.59
46.44
12.29
4.58
3.29
3.25
6.67
.12.50
19.21
61.79
15.17
8.39
6.33
4.06
12.61
21.00
23.64
91.20
15.23
9.88
6.98
5.65
12.33
21.37
26.85
98.29
12.25
8.45
5.98
4.04
11.17
22.20
26.82
90.91
a/ Planted December 29, 1972; figures are
plants/row, 4 replications.
Source: R. Buranday, undergraduate thesis
rpcA.
based on 12 observed
research in progress,
0
0
0
Ca
m
W.
o
M
H I. H I
M H I.
et 0 0
0 H
03 0
o oti
o00 o
M l W H .
9)
rt
10'
(p
4
0p
SC
r of dominant macroarthropods associated with decomposing crop litters. IRRI June-September, 1973.1/
eat- Stratiomyiidae larvae Dermaptera Staphylinidae Spiders
at f Days after seeding Days after seeding Days after seeding Days after seeding
rn- 20 29 37 Total 29 29 37 Total 20 29 37 Total 20 29 37 Total
Corn
pel 804.4 38.9
then 304.4 55.6
pel 6.7 44.4
then 102.2 44.4
133.3 976.6 62.2 11.1 0 73.3 24.4 16.7 88.9 130.0 20.0 0 11.1 31.1
61.1 421.1 26.7 5.6 11.1 43.4 73.3 0 50.0 123.3 42.2 11.1 0 53.3
0 51.1 0 0 5.6 5.6 62.2
33.3 179.9 75.6 66.7 0 142.3 62..2
Mung
38.9
44.4
72.2 173.3
72.2 178.8
42.12
6.7
0
1i1.1
5.6 47.8
5.6 23.4
0 146.7
5.6 634.5.
5.6
5.6.
57.9
44.5
37.8 38.9
13.3 5.6
5.6 82.3 48.9 5.6
0 18.9 13.3 27.8
0 54.5 24.4
22.2 63.3 53.3
20.0' 1111 5.6 36.7 11.1 61.1 11.1 83.13
26.7 22.2 5.6 54.5 57.8 11.1 33.3 102.2
11.1 16.7 52.2
11.1 5.6 70.0
55.6 11.1 11.1 77.8
42.2 50.0 11.1 103.3
Peanut
pel
thene
1631.1
1433.3
,el 1717.8
:hene 3013.3
33.3
122.2
72.2
200.0
11.1 1675.5
11.1 1566.6
11.1 1801.1
5.6 3218.9
20.0
22.2
5.6 0
16.7 '0
33.3 5.6 0
66.7 16.7 0
:25.6 97.8 44.4 27.8 170.0 80.0
38.9 17.8 27.8 5.6 51.2 84.4
38.9 86.7 16.7 27.8 131.2 1441.4
83.4 104.4 61.1 27.8 193.3 )04-.4
11.1
11.1
16,7
11.1
107.8
106.6
33.3 22.2 199.9
16.7 5.6 126.7
hinted June 7, 1973
pray with Dipel at 10 g/19 liters and Orthene at 0.05% a.i. spray solution (starting 28 DAS)
?el
thene
?el
then
146.7
628.9
46.7
33.3
0
0
5.6
5.6
Table 5. Population of fungi and bacteria in crop litters under corn
and treated
with molasses. N2 I June -August, 973./
with molasses. N2 IRRI, June -August, 1973.-
Sampling Layer
Crop Treatment.. Litter Soil Soil
Litter of litter layer 0-5 cm 5-10 cm Total
Fungi, number/g x 103
1. Corn
2. Mung
3. Peanut
4. No litter
Molasses
No molasses
Molasses
No molasses
Molasses
No molasses
Molasses
No molasses
Bacteria, number/g x 103
1. Corn
2. Mung
3. Peanut
4. No litter
Molasses
No molasses
Molasses
No molasses
26,000
8,700
2,370
11,000
Molasses 17,000
No molasses 17,000
Molasses
No molasses
810
310
41
1600
430
264
140
96
120
100
12
100
8
6
964
411
1375
169
1714
1883
462
376
838
15
11
26
730
400
1,410
780
8,700
1,200
800
910
640
100
250
330
1,100
670
100
100
27,370
9,200
36,570
4,030
:12,110
16,140
26,800
18,870
45,670
900
1,010
1,910
a/ Sampled 26 days after seeding of corn.
Source: E. Paterno and R. Aspiras, Dept. of Soil Science,'UPCA.
Table 6. Toxicity of several insecticides to the 'prairek spider
Lycosa sp. Values are corrected percent reduction of nests per
site, mean of 3 sites. CES, April 1973.
Brand name --
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
a/ All insecticides app
a.i. spray solution.
Days after applicationr
3 7 4
First test Second test
26.5 5.4 0
12.3 6.4 0
19.6 0.6 28.7
40.2 37.1
59.5 62.8
13.5 0.3 0
20.4 2.1 1.3
42.2 35.2
13.2 15.4
59.8 51.4
33.8 27.8
18.0 19.1.
27.6 12.5
9.9 11.9 8.3
9.0 12.1 20.0
28.0 34.2
23.5 14.0, 2.7
9.9 7.7 1.4
64.9 40.6
28.5 8.4 :
lied at the uniform rate of 0.05%
Ambithion-
Basrex
Dipterex
Dowco 214
Dursban
Etrofolan
Gardona
JF 484
Kilval
Lannate
Lebaycid
Lepidex
Malathion
Methoxychlor
Mipcin
Orthene
Padan
Pirimicarb
Sumithion
Thiodan
Table 7. Effectiveness of chlorpyrifos against insect pests of
mung. UPCA, May-June 1973.
% Active ingredients .050 .025 .0125 .0062 .0031 .0016 0
Mean yielda/ 1173 833 813 933 713 680 637
a/ In kg/ha. extrapolated.from 10 sq m.
tons. F-test value for differences
highly significant.
plots, 3 replica-
among means is
Source: From F. Guevarra, undergraduate thesis research'in
progress.
Table 8. Insecticidal protection (Dipel, 10 g/5 gal) of cabbage (K-K cross) from the diamond back-moth,
Plutella xylostella. UPCA, January-February 1973
Treat- Number of weeks after transplanting- Average yield (kg/head) Yield
meant 0 1 2 3 4 5 6 7 8 r1 r2 Mean (kg/ha)
No.
1 x x x x x x x .747
2 x x x x x x .638
3 x x x x x .607
4 x x x x .534
5 x x x .411
6 x .297
7 x .075
8 x x x x x x .616
9 x x x x x .604
0L x x x x .270
.1 x x x .281
.2 x x .016
3 x .027
.4 .008
(69)
(74)
(69)
(74)
(79)
(75)
(75)
(76)
(74)
(73)
(70)
(74)
(71)
(70)
...500
.693
.421
.453
.316
.171
.055
.692
.385
.302
.366
.075
.013
(75)
(78)
(74)
(80)
(73)
(72)
(78)
(76)
(75)
(72)
(73)
(80)
(68)
.048 (65)
.624
.666
.514
.494
.364
.234
.065
.654
.494
.286
.324
.046
.020
.028
20,800
22,200
17,133
16,466
12,133
7,800
2,167
21,800
16,466
9,533
10,800
1,533
667
933
a/ Planted December 29, 1972;
x indicates spray applications
Source: M. Lumaban, undergraduate thesis research in progress, UPCA.
Table 9 Insecticidal protection (Orthene, 0.05% a.i.) of mung
(MG50-10A) and bush sitao (E.G. #2). UPCA, May-June, 1973.
Treatment Growth Stages'/ Yield (k/ha)
No A B C D Mung- Bush sitaoE/
1 x x x x 505 1040
2 x x x 555 768
3 x x 535 722
4 x x 70 102
5 x x x 630 862
6 x x 635 885
7 x 460 275
8 x 510 295
9 x 250 0
10 x 260 25
11 5 38
/ From seedling (A) to initial pod frmation (D); x indicates
spray
/ Based
c/ Based
Source:
application.
on dry seed from 10 sq m plots; mean of 2 replications.
on dry pods from 10 sq m plots; mean of 2 replications.
M. Lumaban and E. Cardona .undergraduate thesis research
in progress.
* ,- 1 ..
1 Flora Fauna Flora /
3r Metabolic
liatin Primary Consumers ht
liation heat loss
lit M Secondary Consumers *
S Decomposers **
CROP LITTER
Fig. 1. A model of a multiple cropping ecological system;
consumer trophic levels could be more than two.
Number
25
0 % II I I I I I I
50
25-
oL0 I i -\
30 40 50 60 70 80 90
Days after seeding
Fig. 2. Abundance of the brown planthopper (N. lugens) and
spiders on C463G treated with azinphosmethyl
(Gusathion) and Bacillus thuringiensis (Dipel).
N6 IRRI, August-November 1972. Legend: macropterous
planthoppers (---- ), and spiders (o------o) per 30
insect net sweepings; planthopper nymphs, 3-5 instars
(x___ x) per 1-ft row-hill by beating; arrows ( 4 )
are insecticidal applications. From: R. Lucero,
undergraduate thesis research in progress, UPCA.
IUlo
Days after transplanting
Fig. 3. Abundance of the brown planthopper nymphs and two
spiders, Lycosa pseudoannulata and Theridion sp.,
on C463G. B37 IRRI, April-July 1973. From: A. Gavarra
and R. Lucero, graduate and undergraduate thesis research
in progress, UPCA.
Saprophagous acarines (no./pocket)
150
Ltter further treated with
ozinphosmethyl
100 -
50 Litter from azinphosmethyl
treated crop
Untreated
0
0 10 20 30 40
Days in soil
50 60
Saprophogous acarines (no./pocket)
150 I
0 10 20 30 40 50 60
Days in soil
Fig. 4a. Abundance of saprophagous acarines /Pyemotidae, Uro-
podidae, Oribatei in buried rice litter under corn.
N6 IRRI, January-February, 1973.
Source: A. Sayaboc, undergraduate thesis research in
progress, UPCA.
Collembola (no./pocket)
150 I
10 20 30 40 50
Days in soil
Collembola (no./pocket)
1501
10 20 30 40 50
Days in soil
Fig. 4b. Abundance of seprophagous saoei es fCollembola- in
buried rice litter under corn. N6 IRRI, January-
February, 1973.
Source: A. Sayaboc, undergraduate thesis research in
progress, UPCA.
Predatory acarines (no/podet)
30
20 -
10 -
I I I I I
10 20 30 40 50
Days in soil
Predatory acarines (no./pocket)
30 1
Untreated
Litter from
azinphosmethyl -
further treated
with azinphosmethyl
ir
0 10 20 30 40 50 60
Days in soil
Fig. 4c. Abundance of predatory acarines LDigamasellidae, Rhoda-
caridae, Eupodidae/in buried rice litter under corn.
N6 IRRI, January-February, 1973.
Source: A. Sayaboc, undergraduate thesis research in
progress, UPCA.
Litter further treated with Dipel
/ Litter from Dipel-treated crop
20 -
10o -
mt
m
Inm./Em.
1.07
19 8
0.75
1.00
1.03
19
18
3 C (1) 19
15
-- ---16--
5 C+P (2) 6
15
C (3)
28
"""'--- -"""-
C+P (4)
13117
15113
6 C (5) 20
54
54
15 C+P (6) 25
31
52
20 C (7) 12
36
37
16 C+P (8) 29
49
A. Gusathion-treated
Spiders released.
Imm./Em. (1) 1.22
(2) 0.78
B. No pesticides
No spiders released
(3) 0.97
(4) 1.06
C. No pesticides
Spiders released
(5) 0.83
(6) 0.83
C. Dipel-treated
Spiders released
(7) 1.29
(8) 0.97
Fig. 5. Spider flux in corn and corn-peanut crops with Gusathion
or Dipel treatments. Rate of spider release, one Lycosa
pseudoannulata adult per 3 corn plants. Imm./Em. is ra-
tio of immigration and emigration. N6 IRRI July 22-26,
1973.
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