A manual of rice seed health testing - IRRI books - International Rice ...

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CHAPTER 13 Insect pests J.A. Litsinger and A.T. Barrion Several dozen insect pests feed on rice seeds in storage. Although the rice plant's tough husk is naturally resistant to most insect pests, several species can penetrate the seed. These are called primary pests. Primary pests are of greatest interest to quarantine. Most species, however, are secondary pests that cannot enter or feed in whole grains. Nevertheless, poor storage and handling practices can create quarantine problems where secondary pests have been introduced from one country to another in infested rice straw (e.g., stem borer and rice water weevil). No field pests can be transferred in whole grains. The pests discussed here are pests of stored grain. This group of pests can present minimal quarantine risk if the following procedures are followed: Ship only whole seeds, eliminating broken grain and detritus from seed lots, Do not dry seed in the sun as excessive heat creates openings between the lemma and palea, allowing secondary pests to enter the whole seed. Do not stack seed as this creates pressure that opens the lemma and palea. Fumigate seeds to kill all insects that may be inside. Rice moth Scientific name: Corcyra cephalonica (Stainton) Common name: rice moth Quarantine status: secondary pest Stage of entrance or attachment to seed: larva, egg The adult's body is 12-15 mm long and uniformly gray-brown. Diagnostic features are the upper side of the forewing without spots but with moderately darkened veins; and straight labial palps that are short and inconspicuous in the male but long and prominent in the female. The moth lives for 1 wk. Each female lays 100-300 eggs on grain and in crevices. Larvae develop in silken chambers that are attached to milled rice. Pupal cocoons are dense, white, tough, and occur in clumps. Larvae are dirty white; the first abdominal segment bears a pigmented ring enclosing a membranous area around the base of the seta; abdominal spiracles have the posterior rim prominently thicker than the anterior part. The life cycle of the rice moth is 5-7 wk. The moth commonly attacks rough rice and is rarely found in flour mills. Rusty red grain beetle Scientific name: Cryptolestes ferrugineus (Stephens) Common name: rusty red grain beetle Quarantine status: primary pest Stage of entrance or attachment to seed: larva The adult's body is 1.5-2 mm long and light reddish brown. The rusty red grain beetle can be confused with Cryptolestes pusillus Schönherr (see figure on p. 70) or C. turcicus Grouvelle. Its diagnostic features are an extremely flat and rectangular body; V-shaped, threadlike antennae; and a thorax with lateral ridges strongly to moderately contracted posteriorly. The beetle lives 6-9 mo. Females lay an average of 423 eggs in cracks and crevices of the grain, or loosely in farinaceous material, in intergranular spaces, and in grain dust. Many larvae are found outside the grain kernel. Larvae spin cocoons and prefer the embryo to the endosperm. They complete their development exclusively on some species of seedborne fungi. Larvae are white to straw-colored with flat slender bodies; the posterior end of the abdomen has two dark slender horns. The life cycle lasts 4-9 wk.
Cryptolestes pusillus Schonherr The rusty red grain beetle thrives in hot moist grain. Larvae are coldhardy, tolerant of low relative humidity, and have a climatic plasticity index of 570. The adult is a strong flier. Saw-toothed grain beetle Scientific name: Oryzaephilus surinamensis (Linnaeus) Common name: saw-toothed grain beetle Quarantine status: primary pest Stage of entrance or attachment to seed: none The adult’s body is 2.5-3.5 mm long and dark brown. Although the sawtoothed beetle can be confused with the merchant grain beetle ( O. mercator ), O. surinamensis has smaller eyes and longer rounded checks behind the eyes. Diagnostic features include a flat body and the prothorax bears six prominent teeth along each side and three longitudinal ridges on the dorsal side. The adult usually lives 6-10 mo, but may survive as long as 3 yr. Each adult female lays 50- 400 eggs loose among grains. Larvae feed on the external parts of broken grains. They have long white bodies, brown heads, and three pairs of distinct legs behind the head; and the abdomen tapers posteriorly. The larvae form a protective chamber by sticking small food particles together. The life cycle is 4-5 wk. The saw-toothed grain beetle can tolerate high moisture content in grain. Undamaged seeds or kernels are immune to attack, unless they are moist and soft. The beetle is coldhardy, tolerant of low relative humidity, and has a climate plasticity index of 500. Scarring and roughing of the food or grain surface indicates feeding damage of this beetle. The adult is very active but rarely flies. Indian meal moth Scientific name: Plodia interpunctella (Hubner) Common name: Indian meal moth or dried fruit moth Quarantine status: primary pest Stage of entrance or attachment to seed: larva, egg The adult’s body is 16 mm long and reddish brown. It may be confused with the rice moth Corcyra cephalonica. Diagnostic features are the basal half of the forewing is pale yellow to whitish gray with occasional dark spots; the rest of the body is reddish brown with a coppery luster and pale to dark transverse, irregular, leaden gray stripes. At rest, the wings are folded closely together like a roof along the bodyline and antennae lie flat on the wings. Mutant forms are common— e.g., forms without normal color patterns or with uniformly dark forewings. The adult lives 14 d. Each female lays 40-400 eggs on grain. Larvae feed on both external and internal parts of the rice. They prefer the embryo. Larval color depends on the food consumed. Larvae spin silk to bind grains together and then spin a web over the grains. Larvae have dirty white legs (3 pairs on the thorax and 4 on the abdomen) along a hairy body. Each side of the head has 5-6 eye spots. The front of the head extends slightly more than two-thirds into a vertical triangle. The life cycle is 3-8 wk. 70 Rice seed health testing manual
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A Manual of Rice Seed Health Testin
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Contents Foreword v Preface vi Part
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Foreword Intensive collaboration ch
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Part 1 Introduction CHAPTER 1 Rice
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tional levels (Kahn 1988). Quaranti
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Morphology of the mature plant Matu
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two-celled, besifixed, deeply sagit
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Part 2 Procedures for seed health e
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CHAPTER 3 Equipment J.K. Misra, T.W
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3.2 Dry seed inspection using a mag
Page 25 and 26: Example. In a two-stage random samp
Page 27 and 28: solid pointed end. The tube and sle
Page 30: CHAPTER 5 Dry seed inspection J.K.
Page 33 and 34: Detection Blotter and agar plate me
Page 35 and 36: Results: Examine plates for charac-
Page 37 and 38: Extraction and isolation It is esse
Page 39 and 40: GRINDING METHOD (FOR SMALL-SCALE SE
Page 41 and 42: flagellum. Cells occur singly, in p
Page 43 and 44: 7.6 Oxidase test reaction. L = colo
Page 45 and 46: 7.9 Production of 2-ketogluconate.
Page 47 and 48: 1. Grow pathogen-free plants under
Page 49 and 50: 7.12 a. P. glumae type A colony on
Page 51 and 52: A1. Macerate 100 seeds in 10 ml of
Page 53 and 54: Results: 7.Streak the bacteria onto
Page 55 and 56: Sieve method (Fig. 8.1) Procedure:
Page 58 and 59: CHAPTER 10 Field inspection J.K. Mi
Page 60 and 61: Table 10.2. continued Disease Fungi
Page 62 and 63: Table 10.2. continued Disease Growt
Page 64: additional precaution, the multipli
Page 67 and 68: terracoat (5-ethoxy-3- trichloromet
Page 70: Part 3 Pests and pathogens CHAPTER
Page 73 and 74: elevant tests for determining the i
Page 75: Table 12.1 continued Family and spe
Page 79 and 80: Rice weeviI Scientific name: Sitoph
Page 82 and 83: CHAPTER 14 Fungal pathogens J.K. Mi
Page 84 and 85: THE DISEASE—BROWN SPOT Sir John W
Page 86 and 87: Symptoms Glumes are discolored, and
Page 88 and 89: y low relative humidity. Released a
Page 90 and 91: THE DISEASE—STEM ROT Stem rot was
Page 92 and 93: THE DISEASE—SHEATH BLIGHT Sheath
Page 94 and 95: Sarocladium oryzae is seedborne. Th
Page 96: Although not currently considered a
Page 99 and 100: Pseudomonas fuscovaginae Pathogen:
Page 101 and 102: See Chapter 7 and Figure 15.4a for
Page 103 and 104: Infected seeds and contaminated wat
Page 105 and 106: For further details, see the Common
Page 107 and 108: nonfluorescent) and Erwinia herbico
Page 109 and 110: Franklin M T, Siddiqi M R (1972) Ap
Page 111 and 112: Tai F L, Siang W N (1948) 'I-chu-hs
Page 113 and 114: 106 Rice seed health testing manual
Page 115 and 116: 108 Rice seed health testing manual
Page 117 and 118: After autoclaving the medium, add t
Page 119 and 120: smoniloid = having swellings at reg
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